Patent Publication Number: US-11657783-B2

Title: Display device and operating method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of U.S. application Ser. No. 15/687,037, filed Aug. 25, 2017, which claims the benefits of priority to Korean Patent Application No. 10-2017-0063604 filed on May 23, 2017, which are herein incorporated by reference in their entirety. 
    
    
     FIELD 
     The present invention relates to a display device and, more particularly, to a display device including a flexible display. 
     BACKGROUND 
     A display device has a function for receiving, processing and displaying an image viewable by a user. The display device receives a broadcast signal selected by a user from among broadcast signals transmitted by a broadcaster, divides a video signal from the received signal, and displays the divided video signal on a display. 
     Recently, with development of broadcast technology and network technology, various functions have been added to the display device and performance of the device has been improved. That is, the display device has been developed to provide a variety of content to a user in addition to broadcast content. For example, the display device can provide game playing, music, Internet shopping, customized information, etc. using various applications as well as programs received from a broadcaster. In order to perform such functions, the display device may be connected to other devices or a network using various communication protocols to provide ubiquitous computing to the user. That is, the display device has evolved into a smart device enabling connectivity to a network and ubiquitous computing. 
     Recently, a flexible display having sufficient elasticity has been developed. Such a flexible display can be rolled into the main body of a display device. The display device includes such a flexible display. Further, the display device may include a rollable display unit having an outwardly protruding area changed by winding or unwinding the display in a direction guided by a guide bar. By using the rollable display unit, the display device can have a more compact structure. 
     SUMMARY 
     An object of the present invention is to provide a display device for providing a convenient user experience and user interface to a user using the properties of a rollable display unit, and a method of operating the same. 
     According to an embodiment of the present invention, a display device including a housing, a rotatable guide bar accommodated in the housing, a display unit withdrawn from or inserted into the housing according to rotation of the guide bar, and a controller configured to display first content in a first region withdrawn from the housing, to withdraw the display unit to add a second region if a second-content display command is received, and to display second content in the second region. 
     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings, which are given by illustration only, and thus are not limitative of the present invention, and wherein: 
         FIG.  1    is a block diagram illustrating the configuration of a display device according to an embodiment of the present invention. 
         FIG.  2    is a block diagram illustrating a remote control device according to an embodiment of the present invention. 
         FIG.  3    is a view illustrating an actual configuration of a remote control device according to an embodiment of the present invention. 
         FIG.  4    is a view showing an example of utilizing a remote control device according to an embodiment of the present invention. 
         FIGS.  5 A to  5 F  are views illustrating a method of operating a display unit according to an embodiment of the present invention. 
         FIGS.  6 A and  6 B  are flowcharts illustrating a method of operating a display device according to an embodiment of the present invention. 
         FIG.  7 A  is a diagram illustrating a method of displaying a menu in a region of a display device withdrawn in a longitudinal direction according to a first embodiment of the present invention. 
         FIG.  7 B  is a diagram illustrating a method of displaying a menu in a region of a display device withdrawn in a longitudinal direction according to a second embodiment of the present invention. 
         FIG.  7 C  is a diagram illustrating a method of displaying a menu in a region of a display device withdrawn in a longitudinal direction according to a third embodiment of the present invention. 
         FIG.  7 D  is a diagram illustrating a method of displaying a menu in a region of a display device withdrawn in a longitudinal direction according to a fourth embodiment of the present invention. 
         FIGS.  8 A to  8 C  are diagrams illustrating a method of displaying a menu in a region of a display device withdrawn in a height direction according to a first embodiment of the present invention 
         FIGS.  9 A to  9 C  are diagrams illustrating a method of displaying a menu in a region of a display device withdrawn in a height direction according to a second embodiment of the present invention. 
         FIGS.  10 A to  10 C  are diagrams illustrating a method of displaying content corresponding to an item selected from a menu in a first region according to an embodiment of the present invention. 
         FIGS.  11 A and  11 B  are diagrams illustrating a method of displaying content corresponding to an item selected from a menu in a second region according to a first embodiment of the present invention. 
         FIGS.  12 A and  12 B  are diagrams illustrating a method of displaying content corresponding to an item selected from a menu in a second region according to a second embodiment of the present invention. 
         FIGS.  13 A to  13 C  are diagrams illustrating a method of changing a display region of content according to an embodiment of the present invention. 
         FIGS.  14 A to  14 C  are diagrams illustrating a method of displaying content upon connection with an external device according to a first embodiment of the present invention. 
         FIGS.  15 A to  15 B  are diagrams illustrating a method of displaying content upon connection with an external device according to a second embodiment of the present invention. 
         FIGS.  16 A and  16 B  are diagrams illustrating a method of displaying content upon connection with a plurality of external devices according to an embodiment of the present invention. 
         FIG.  16 C  is a diagram illustrating a method of inserting a display unit based on disconnection of an external device according to an embodiment of the present invention. 
         FIGS.  17 A to  17 D  are diagrams illustrating a method of displaying content based on a voice command signal according to an embodiment of the present invention. 
         FIGS.  18 A and  18 B  are diagrams illustrating a method of displaying content based on a display-unit withdrawal command according to a first embodiment of the present invention. 
         FIGS.  19 A and  19 B  are diagrams illustrating a method of displaying content based on a display-unit withdrawal command according to a second embodiment of the present invention. 
         FIG.  20    is a diagram illustrating a method of displaying content based on a display-unit withdrawal command according to a third embodiment of the present invention. 
         FIG.  21    is a diagram illustrating a method of displaying content based on a display-unit withdrawal command according to a fourth embodiment of the present invention. 
         FIGS.  22 A and  22 B  are diagrams illustrating a method of displaying content based on a display-unit withdrawal command according to a fifth embodiment of the present invention. 
         FIGS.  23 A and  23 B  are diagrams illustrating a first example of a method of displaying content based on a display-unit withdrawal command according to a sixth embodiment of the present invention. 
         FIGS.  24 A and  24 B  are diagrams illustrating a second example of a method of displaying content based on a display-unit withdrawal command according to a sixth embodiment of the present invention. 
         FIGS.  25 A to  25 C  are diagrams illustrating a method of displaying content based on a display-unit withdrawal command according to a seventh embodiment of the present invention. 
         FIGS.  26 A to  26 C  are diagrams illustrating a first example of a method of displaying content based on a display-unit withdrawal command according to an eighth embodiment of the present invention. 
         FIGS.  27 A to  27 C  are diagrams illustrating a second example of a method of displaying content based on a display-unit withdrawal command according to an eighth embodiment of the present invention. 
         FIGS.  28 A to  28 C  are diagrams illustrating a third example of a method of displaying content based on a display-unit withdrawal command according to an eighth embodiment of the present invention. 
         FIGS.  29 A to  29 C  are diagrams illustrating a method of displaying content based on a display-unit withdrawal command according to a ninth embodiment of the present invention. 
         FIGS.  30 A to  30 C  are diagrams illustrating an operation method based on a display-unit insertion command according to an embodiment of the present invention. 
         FIGS.  31 A to  31 C  are diagrams illustrating a method of displaying content according to a viewing mode entrance command according to a first embodiment of the present invention. 
         FIGS.  32 A to  32 C  are diagrams illustrating a method of displaying content based on a viewing mode entrance command according to a second embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, embodiments relating to the present invention will be described in detail with reference to the accompanying drawings. The suffixes “module” and “unit” for components used in the description below are assigned or mixed in consideration of easiness in writing the specification and do not have distinctive meanings or roles by themselves. 
     The display device described in this specification refers to a TV, a smart TV, a network TV, a hybrid broadcast broadband television (HBBTV), an Internet TV, a web TV, an Internet protocol television (IPTV), digital signage, a desktop computer, a smartphone, a laptop computer, a digital broadcast terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation system, a slate PC, a tablet PC, an ultrabook, a wearable device, etc. including a rollable display unit. Here, rollable display unit means that a display unit may be rolled in the form of a roll and may include a flexible display, a foldable display, etc. 
       FIG.  1    is a block diagram illustrating a configuration of a display device according to an embodiment of the present invention. Referring to  FIG.  1   , a display device  100  can include a broadcast reception unit  130 , an external device interface unit  135 , a storage unit  140 , a user input interface unit  150 , a control unit  170 , a wireless communication unit  173 , a display unit  180 , an audio output unit  185 , and a power supply unit  190 . 
     The broadcast reception unit  130  can include a tuner  131 , a demodulation unit  132 , and a network interface unit  133 . The tuner  131  can select a specific broadcast channel according to a channel selection command. The tuner  131  can receive broadcast signals for the selected specific broadcast channel. 
     The demodulation unit  132  can divide the received broadcast signals into video signals, audio signals, and broadcast program related data signals and restore the divided video signals, audio signals, and data signals to an output available form. The network interface unit  133  can provide an interface for connecting the display device  100  to a wired/wireless network including internet network. The network interface unit  133  can transmit or receive data to or from another user or another electronic device through an accessed network or another network linked to the accessed network. 
     Additionally, some content data stored in the display device  100  can be transmitted to a user or an electronic device, which is selected from other users or other electronic devices pre-registered in the display device  100 . The network interface unit  133  can access a predetermined webpage through an accessed network or another network linked to the accessed network. That is, it can transmit or receive data to or from a corresponding server by accessing a predetermined webpage through network. 
     Then, the network interface unit  133  can receive contents or data provided from a content provider or a network operator. That is, the network interface unit  133  can receive contents such as movies, advertisements, games, VODs, and broadcast signals, which are provided from a content provider or a network provider, through network and information relating thereto. Additionally, the network interface unit  133  can receive firmware update information and update files provided from a network operator and transmit data to an internet or content provider or a network operator. The network interface unit  133  can select and receive a desired application among applications open to the air, through network. 
     The external device interface unit  135  can receive an application or an application list in an adjacent external device and deliver it to the control unit  170  or the storage unit  140 . The external device interface unit  135  can provide a connection path between the display device  100  and an external device. In addition, the external device interface  135  can receive at least one of image and audio output from an external device that is wirelessly or wiredly connected to the display device  100  and deliver it to the control unit. The external device interface unit  135  can include a plurality of external input terminals. The plurality of external input terminals can include an RGB terminal, at least one High Definition Multimedia Interface (HDMI) terminal, and a component terminal. 
     An image signal of an external device input through the external device interface unit  135  can be output through the display unit  180 . A sound signal of an external device input through the external device interface unit  135  can be output through the audio output unit  185 . An external device connectable to the external device interface unit  130  can be one of a set-top box, a Blu-ray player, a DVD player, a game console, a sound bar, a smartphone, a PC, a USB Memory, and a home theater system but this is just exemplary. 
     The storage unit  140  can store signal-processed image, voice, or data signals stored by a program in order for each signal processing and control in the control unit  170 . Additionally, the storage unit  140  can perform a function for temporarily store image, voice, or data signals output from the external device interface unit  135  or the network interface unit  133  and can store information on a predetermined image through a channel memory function. The storage unit  140  can store an application or an application list input from the external device interface unit  135  or the network interface unit  133 . 
     The display device  100  can play content files (for example, video files, still image files, music files, document files, application files, and so on) stored in the storage unit  140  and provide them to a user. The user input interface unit  150  can deliver signals input from a user to the control unit  170  or deliver signals from the control unit  170  to a user. For example, the user input interface unit  150  can receive or process control signals such as power on/off, channel selection, and screen setting from the remote control device  200  or transmit control signals from the control unit  170  to the remote control device  200  according to various communication methods such as Bluetooth, Ultra Wideband (WB), ZigBee, Radio Frequency (RF), and IR. 
     Additionally, the user input interface unit  150  can deliver, to the control unit  170 , control signals input from local keys such as a power key, a channel key, a volume key, and a setting key. Image signals that are image-processed in the control unit  170  can be input to the display unit  180  and displayed as an image corresponding to corresponding image signals. Additionally, image signals that are image-processed in the control unit  170  can be input to an external output device through the external device interface unit  135 . 
     Voice signals processed in the control unit  170  can be output to the audio output unit  185 . Additionally, voice signals processed in the control unit  170  can be input to an external output device through the external device interface unit  135 . Further, the control module  170  can control overall operations in the display device  100 . 
     Additionally, the control unit  170  can control the display device  100  by a user command or internal program input through the user input interface unit  150  and download a desired application or application list into the display device  100  in access to network. The control unit  170  can output channel information selected by a user together with processed image or voice signals through the display unit  180  or the audio output unit  185 . 
     Additionally, according to an external device image playback command received through the user input interface unit  150 , the control unit  170  can output image signals or voice signals of an external device such as a camera or a camcorder, which are input through the external device interface unit  135 , through the display unit  180  or the audio output unit  185 . 
     Moreover, the control unit  170  can control the display unit  180  to display images and control broadcast images input through the tuner  131 , external input images input through the external device interface unit  135 , images input through the network interface unit, or images stored in the storage unit  140  to be displayed on the display unit  180 . In this instance, an image displayed on the display unit  180  can be a still image or video and also can be a 2D image or a 3D image. 
     Also, the control unit  170  can play content stored in the display device  100 , received broadcast content, and external input content input from the outside, and the content can be in various formats such as broadcast images, external input images, audio files, still images, accessed web screens, and document files. 
     Further, the wireless communication unit  173  can perform a wired or wireless communication with an external electronic device. The wireless communication unit  173  can perform short-range communication with an external device. For this, the wireless communication unit  173  can support short-range communication by using at least one of Bluetooth™, Radio Frequency Identification (RFID), Infrared Data Association (IrDA), Ultra Wideband (UWB), ZigBee, Near Field Communication (NFC), Wireless-Fidelity (Wi-Fi), Wi-Fi Direct, and Wireless Universal Serial Bus (USB) technologies. The wireless communication unit  173  can support wireless communication between the display device  100  and a wireless communication system, between the display device  100  and another display device  100 , or between networks including the display device  100  and another display device  100  (or an external server) through wireless area networks. The wireless area networks can be wireless personal area networks. 
     Herein, the other display device  100  can be a mobile terminal such as a wearable device (for example, a smart watch, a smart glass, and a head mounted display (HMD)) or a smartphone, which is capable of exchanging data (or inter-working) with the display device  100 . The wireless communication unit  173  can detect (or recognize) a communicable wearable device around the display device  100 . Furthermore, if the detected wearable device is a device authenticated to communicate with the display device  100 , the control unit  170  can transmit at least part of data processed in the display device  100  to the wearable device through the wireless communication unit  173 . Accordingly, a user of the wearable device can use the data processed in the display device  100  through the wearable device. The wireless communication unit  173  can be provided separated from the external device interface unit  135  and can be included in the external device interface unit  135 . 
     The display unit  180  can convert image signals, data signals, or OSD signals, which are processed in the control unit  170 , or images signals or data signals, which are received in the external device interface unit  135 , into R, G, and B signals to generate driving signals. The display unit  180  may include a rollable display unit. 
     The rollable display unit may mean that a display unit for displaying content may be inserted to be wound on a guide bar or may be withdrawn to be unwound from the guide bar. The display device  100  may include the rollable display unit. A region, in which content is displayed, may increase or decrease according to withdrawal or insertion of the rollable display unit. The below-described display unit  180  may include the rollable display unit. 
     Furthermore, the display device  100  shown in  FIG.  1    is just one embodiment of the present invention and thus, some of the components shown can be integrated, added, or omitted according to the specification of the actually implemented display device  100 . That is, if necessary, two or more components can be integrated into one component or one component can be divided into two or more components and configured. Additionally, a function performed by each block is to describe an embodiment of the present invention and its specific operation or device does not limit the scope of the present invention. 
     According to another embodiment of the present invention, unlike  FIG.  1   , the display device  100  can receive images through the network interface unit  133  or the external device interface unit  135  and play them without including the tuner  131  and the demodulation unit  132 . For example, the display device  100  can be divided into an image processing device such as a set-top box for receiving broadcast signals or contents according to various network services and a content playback device for playing contents input from the image processing device. 
     In this instance, an operating method of a display device according to an embodiment of the present invention described below can be performed by one of the display device described with reference to  FIG.  1   , an image processing device such as the separated set-top box, and a content playback device including the display unit  180  and the audio output unit  185 . 
     Next, referring to  FIGS.  2  and  3   , a remote control device is described according to an embodiment of the present invention.  FIG.  2    is a block diagram illustrating a remote control device according to an embodiment of the present invention and  FIG.  3    is a view illustrating an actual configuration of a remote control device according to an embodiment of the present invention. 
     First, referring to  FIG.  2   , a remote control device  200  can include a fingerprint recognition unit  210 , a wireless communication unit  220 , a user input unit  230 , a sensor unit  240 , an output unit  250 , a power supply unit  260 , a storage unit  270 , a control unit  280 , and a voice acquisition unit  290 . As shown in  FIG.  2   , the wireless communication unit  225  transmits/receives signals to/from an arbitrary any one of display devices according to the above-mentioned embodiments of the present invention. 
     The remote control device  200  can include an RF module  221  for transmitting/receiving signals to/from the display device  100  according to the RF communication standards and an IR module  223  for transmitting/receiving signals to/from the display device  100  according to the IR communication standards. Additionally, the remote control device  200  can include a Bluetooth module  225  for transmitting/receiving signals to/from the display device  100  according to the Bluetooth communication standards. Additionally, the remote control device  200  can include an NFC module  227  for transmitting/receiving signals to/from the display device  100  according to the Near Field Communication (NFC) communication standards and a WLAN module  229  for transmitting/receiving signals to/from the display device  100  according to the Wireless LAN (WLAN) communication standards 
     Additionally, the remote control device  200  can transmit signals containing information on a movement of the remote control device  200  to the display device  100  through the wireless communication unit  220 . Moreover, the remote control device  200  can receive signals transmitted from the display device  100  through the RF module  221  and if necessary, can transmit a command on power on/off, channel change, and volume change to the display device  100  through the IR module  223 . 
     The user input unit  230  can be configured with a keypad button, a touch pad, or a touch screen. A user can manipulate the user input unit  230  to input a command relating to the display device  100  to the remote control device  200 . If the user input unit  230  includes a hard key button, a user can input a command relating to the display device  100  to the remote control device  200  through the push operation of the hard key button. This will be described with reference to  FIG.  3   . 
     Referring to  FIG.  3   , the remote control device  200  can include a plurality of buttons. The plurality of buttons can include a fingerprint recognition button  212 , a power button  231 , a home button  232 , a live button  233 , an external input button  234 , a voice adjustment button  235 , a voice recognition button  236 , a channel change button  237 , a check button  238 , and a back button  239 . 
     The fingerprint recognition button  212  can be a button for recognizing a user&#39;s fingerprint. According to an embodiment of the present invention, the fingerprint recognition button  212  can perform a push operation and receive a push operation and a fingerprint recognition operation. The power button  231  can be button for turning on/off the power of the display device  100 . The power button  232  can be button for moving to the home screen of the display device  100 . The live button  233  can be a button for displaying live broadcast programs. The external input button  234  can be button for receiving an external input connected to the display device  100 . The voice adjustment button  235  can be button for adjusting the size of a volume output from the display device  100 . The voice recognition button  236  can be a button for receiving user&#39;s voice and recognizing the received voice. The channel change button  237  can be a button for receiving broadcast signals of a specific broadcast channel. The check button  238  can be a button for selecting a specific function and the back button  239  can be a button for returning to a previous screen. 
     Again,  FIG.  2    is described. If the user input unit  230  includes a touch screen, a user can touch a soft key of the touch screen to input a command relating to the display device  100  to the remote control device  200 . Additionally, the user input unit  230  can include various kinds of input means manipulated by a user, for example, a scroll key and a jog key, and this embodiment does not limit the scope of the present invention. 
     The sensor unit  240  can include a gyro sensor  241  or an acceleration sensor  243  and the gyro sensor  241  can sense information on a movement of the remote control device  200 . For example, the gyro sensor  241  can sense information on an operation of the remote control device  200  based on x, y, and z axes and the acceleration sensor  243  can sense information on a movement speed of the remote control device  200 . Moreover, the remote control device  200  can further include a distance measurement sensor and sense a distance with respect to the display unit  180  of the display device  100 . 
     The output unit  250  can output image or voice signals corresponding to a manipulation of the user input unit  235  or corresponding to signals transmitted from the display device  100 . A user can recognize whether the user input unit  235  is manipulated or the display device  100  is controlled through the output unit  250 . For example, the output unit  250  can include an LED module  251  for flashing, a vibration module  253  for generating vibration, a sound output module  255  for outputting sound, or a display module  257  for outputting an image, if the user input unit  235  is manipulated or signals are transmitted/received to/from the display device  100  through the wireless communication unit  225 . 
     Additionally, the power supply unit  260  supplies power to the remote control device  200  and if the remote control device  200  does not move for a predetermined time, stops the power supply, so that power waste can be reduced. The power supply unit  260  can resume the power supply if a predetermined key provided at the remote control device  200  is manipulated. 
     The storage unit  270  can store various kinds of programs and application data necessary for a control or operation of the remote control device  200 . If the remote control device  200  transmits/receives signals wirelessly through the display device  100  and the RF module  221 , the remote control device  200  and the display device  100  transmits/receives signals through a predetermined frequency band. 
     The control unit  280  of the remote control device  200  can store, in the storage unit  270 , information on a frequency band for transmitting/receiving signals to/from the display device  100  paired with the remote control device  200  and refer to it. The control unit  280  controls general matters relating to a control of the remote control device  200 . The control unit  280  can transmit a signal corresponding to a predetermined key manipulation of the user input unit  235  or a signal corresponding to a movement of the remote control device  200  sensed by the sensor unit  240  to the display device  100  through the wireless communication unit  225 . 
     Additionally, the voice acquisition unit  290  of the remote control device  200  can obtain voice. The voice acquisition unit  290  can include at least one microphone  291  and obtain voice through the microphone  291 . 
     Next,  FIG.  4    is described.  FIG.  4    is a view of utilizing a remote control device according to an embodiment of the present invention. In particular,  FIG.  4 ( a )  illustrates that a pointer  205  corresponding to the remote control device  200  is displayed on the display unit  180 . 
     A user can move or rotate the remote control device  200  vertically or horizontally. The pointer  205  displayed on the display unit  180  of the display device  100  corresponds to a movement of the remote control device  200 . Since the corresponding pointer  205  is moved and displayed according to a movement on a 3D space as show in the drawing, the remote control device  200  can be referred to as a spatial remote controller. 
       FIG.  4 ( b )  illustrates that if a user moves the remote control device  200 , the pointer  205  displayed on the display unit  180  of the display device  100  is moved to the left in correspondence thereto. Information on a movement of the remote control device  200  detected through a sensor of the remote control device  200  is transmitted to the display device  100 . The display device  100  can calculate the coordinates of the pointer  205  from the information on the movement of the remote control device  200 . The display device  100  can display the pointer  205  to match the calculated coordinates. 
       FIG.  4 ( c )  illustrates that while a specific button in the remote control device  200  is pressed, a user moves the remote control device  200  away from the display unit  180 . Thus, a selection area in the display unit  180  corresponding to the pointer  205  can be zoomed in and displayed largely. Further, if a user moves the remote control device  200  close to the display unit  180 , a selection area in the display unit  180  corresponding to the pointer  205  can be zoomed out and displayed reduced. 
     If the remote control device  200  is away from the display unit  180 , a selection area can be zoomed out and if the remote control device  200  is close to the display unit  180 , a selection area can be zoomed in. Additionally, if a specific button in the remote control device  200  is pressed, the recognition of a vertical or horizontal movement can be excluded. That is, if the remote control device  200  is moved away from or close to the display unit  180 , the up, down, left, or right movement can not be recognized and only the back and fourth movement can be recognized. While a specific button in the remote control device  200  is not pressed, only the pointer  205  is moved according to the up, down, left or right movement of the remote control device  200 . 
     Moreover, the moving speed or moving direction of the pointer  205  can correspond to the moving speed or moving direction of the remote control device  200 . Furthermore, a pointer in this specification means an object displayed on the display unit  180  in correspondence to an operation of the remote control device  200 . Accordingly, besides an arrow form displayed as the pointer  205  in the drawing, various forms of objects are possible. For example, the above concept includes a point, a cursor, a prompt, and a thick outline. Then, the pointer  205  can be displayed in correspondence to one point of a horizontal axis and a vertical axis on the display unit  180  and also can be displayed in correspondence to a plurality of points such as a line and a surface. 
     Next, the method of operating the display unit  180  according to the embodiment of the present invention will be described with reference to  FIGS.  5 A to  5 F . In particular,  FIGS.  5 A to  5 F  are views illustrating a method of operating a display unit according to an embodiment of the present invention. 
     As shown in  FIG.  5 A , the display device  100  may include a display unit  180  having a first region  181 . The display unit  180  may display content in the first region  181 . The display device  100  may include a guide bar  184  (see  FIG.  5 B ) which may rotate such that the display unit  180  is wound into or unwound from a housing  183  or at the center of the display unit  180 . 
     When the display device  100  includes the guide bar  184  in the housing  183 , the display unit  180  can be wound or unwound in a vertical direction. If the display device  100  includes the guide bar  184  at the center of the display unit  180 , the display unit  180  can be wound or unwound in a horizontal direction. 
     Referring to  FIG.  5 B , when the display unit is wound or unwound by the guide bar according to the embodiment of the present invention will be described.  FIG.  5 B  is a side cross-sectional view of the housing  183  shown in  FIG.  5 A . As shown in  FIG.  5 B , the housing  183  may include the guide bar  184  for guiding the display unit  180  to be wound or unwound. When the guide bar  184  rotates in an R 1  direction, the display unit  180  can be withdrawn from the housing  183 . In contrast, when the guide bar  18  rotates in an R 2  direction, the display unit  180  can be inserted into the housing  183  while being wound on the guide bar  184 . Therefore, the display unit  180  can be withdrawn or inserted in the vertical direction. 
     A cover  186  can protect the display unit  180  inserted into the housing  183 . If the guide bar is located at the center of the display unit  180 , the display unit  180  can be withdrawn or inserted in the horizontal direction according to the principle shown in  FIG.  5 B . As the display unit  180  is withdrawn or inserted, a region capable of displaying content can be changed, that is, increased or decreased. 
     Hereinafter, when, as the display unit is wound or unwound, a content display region is changed will be described with reference to  FIGS.  5 B to  5 F . In the state shown in  FIG.  5 A , the display unit  180  can be withdrawn to have second regions  182  as shown in  FIGS.  5 C to  5 F . 
     Referring to  FIG.  5 C , the display unit  180  according to a first embodiment of the present invention can be withdrawn in left and right directions. The display unit  180  may include a first region  181  and second regions  182  located at both sides of the first region  181 . 
     Referring to  FIG.  5 D , the display unit  180  according to a second embodiment of the present invention can be withdrawn only in a right direction. The display unit  180  may include a first region  181  and a second region  182  located at the right side of the first region  181 . Referring to  FIG.  5 E , the display unit  180  according to a third embodiment of the present invention can be withdrawn only in a left direction. The display unit  180  may include a first region  181  and a second region  182  located at a left side of the first region  181 . 
     Referring to  FIG.  5 F , the display unit  180  according to a fourth embodiment of the present invention can be withdrawn only in an upper direction. The display unit  180  may include a first region  181  and a second region  182  located at an upper side of the first region  181 . As shown in  FIG.  5 F , the second region  182  may be located at the upper side of the first region  181 . Unlike  FIG.  5 F , the second region  182  may be located at a lower side of the first region  181 . 
     The size of the second region  182  can be determined by withdrawal lengths L 1 , L 2 , L 3  and L 4  of the display unit  180 . The withdrawal lengths L 1 , L 2 , L 3  and L 4  of the display unit  180  may be changed. That is, the controller  170  can adjust the withdrawal lengths L 1 , L 2 , L 3  and L 4  according to attributes of content to be displayed, a length adjustment command of a user, etc. to withdraw the display unit  180 . 
     In addition, the withdrawal direction of the display unit  180  may be determined according to attributes of the display device  100  or a user input command. Further, the display unit  180  can display different content or the same content in the first region  181  and the second region  182 . 
     Next, a method of operating a display device  100  according to an embodiment of the present invention will be described with reference to  FIGS.  6 A and  6 B . In particular,  FIGS.  6 A to  6 B  are flowcharts illustrating a method of operating a display device according to an embodiment of the present invention. 
     The display unit  180  can display first content in the first region  181  (S 11 ). The display unit  180  may have only the first region  181  by default. That is, the display device  100  may include only the first region  181  before receiving a specific command. Content corresponding to a broadcast signal received through the broadcast reception unit  130  can be displayed in the first region  181 . 
     The controller  170  can sense whether a menu display command is received (S 13 ). Here, the menu is second content and the menu display command may be a second content display command. The controller  170  can receive the menu display command through a button provided in the remote control device  200  or a button provided in the display device  100 . The controller  170  can sense whether the menu display command is received and can withdraw the display unit to add the second region  182  (S 15 ) when the menu display command is received, and the display unit  180  can display the menu in the withdrawn second region  182  (S 17 ). 
     Next, a method of displaying a menu in a region of a display device withdrawn in a longitudinal direction according to various embodiments of the present invention will be described with reference to  FIGS.  7 A to  7 D , a method of displaying a menu in a region of a display device withdrawn in a height direction according to a first embodiment of the present invention will be described with reference to  FIGS.  8 A to  8 C , and a method of displaying a menu in a region of a display device withdrawn in a height direction according to a second embodiment of the present invention will be described with reference to  FIGS.  9 A to  9 C . 
       FIG.  7 A  is a diagram illustrating a method of displaying a menu in a region of a display device withdrawn in a longitudinal direction according to a first embodiment of the present invention. Referring to  FIG.  7 A , the display unit  180  can be withdrawn in a left direction. The display unit  180  can include only the first region  181  before withdrawal and include the first region  181  and the second region  182  located at the left side of the first region  181  after withdrawal. 
     The display unit  180  can display first content in the first region  181  and display the menu in the second region  182 . The location of the first region  181  may be the same before and after withdrawal. Accordingly, the first content can be continuously displayed at the same location regardless of withdrawal of the display unit  180 . 
     Next,  FIG.  7 B  is a diagram illustrating a method of displaying a menu in a region of a display device withdrawn in a longitudinal direction according to a second embodiment of the present invention. Referring to  FIG.  7 B , the display unit  180  can be withdrawn in a right direction. The display unit  180  can include only the first region  181  before withdrawal and include the first region  181  and the second region  182  located at the right side of the first region  181  after withdrawal. The display unit  180  can display first content in the first region  181  and display the menu in the second region  182 . 
     Similarly to  FIG.  7 A , the location of the first region  181  may be the same before and after withdrawal. Accordingly, the first content can be continuously displayed at the same location regardless of withdrawal of the display unit  180 . 
       FIG.  7 C  is a diagram illustrating a method of displaying a menu in a region of a display device withdrawn in a longitudinal direction according to a third embodiment of the present invention. Referring to  FIG.  7 C , the display unit  180  can be withdrawn in both directions. 
     The display unit  180  can include only the first region  181  before withdrawal and include the first region  181  and the second region  182  located at the right side of the first region  181  after withdrawal. Alternatively, unlike  FIG.  7 C , the display unit  180  can include the first region  181  and the second region  182  located at the left side of the first region  181 . The display unit  180  can display first content in the first region  181  and display the menu in the second region  182 . 
     The controller  170  can shift the first content such that the location of the first region  181  is the same before and after withdrawal. That is, the controller  170  can shift the first content while withdrawing the display unit  180 . Thus, the first content can be continuously displayed at the same location regardless of withdrawal of the display unit  180 , and the menu may be displayed in a region added by withdrawal of the display unit  180 . 
       FIG.  7 D  is a diagram illustrating a method of displaying a menu in a region of a display device withdrawn in a longitudinal direction according to a fourth embodiment of the present invention. Referring to  FIG.  7 D , the display unit  180  can be withdrawn in both directions. 
     The display unit  180  can include only the first region  181  before withdrawal and include the first region  181  and the second regions  182  located at both sides of the first region  181  after withdrawal. The second regions  182  may include a second left region  182   a  and a second right region  182   b.    
     The display unit  180  can display first content in the first region  181  and display the menu in the second region  182 . The second left region  182  and the second right region  182   b  may display different menus. The location of the first region  181  can be the same before and after withdrawal and thus the first content can be continuously displayed at the same location regardless of withdrawal of the display unit  180 . The menu may be displayed in the second left region  182   a  and the second right region  182   b.    
     In the embodiment shown in  FIG.  7 D , more information can be displayed in the second region  182  as compared to the embodiment shown in  FIG.  7 C . In addition, in the embodiments shown in  FIGS.  7 A to  7 D , the display device  100  can display the menu so as not to hide the displayed content. That is, the display device  100  can provide a method of viewing and manipulating the menu while the user views the content without interruption. 
     Although the first content is shifted only in  FIG.  7 C , this is merely an example. That is, in the embodiments of  FIGS.  7 A,  7 B and  7 C  and the subsequent embodiments, the controller  170  can shift the first content in order to fix the location of the first region  181 . 
     Next,  FIGS.  8 A to  8 C  are diagrams illustrating a method of displaying a menu in a region of a display unit withdrawn in a height direction according to a first embodiment of the present invention. As shown in  FIG.  8 A , the display unit  180  can include a first region  181  and first content can be displayed in the first region  181 . 
     When a menu display command is received, the controller  170  can withdraw the display unit  180  in the height direction to add a second region  182  as shown in  FIG.  8 B . The second region  182  may be located below the first region  181 . That is, as the display unit  180  is withdrawn, the first region  181  may rise and the second region  182  may be added. 
     As shown in  FIG.  8 C , the display unit  180  can continuously display the first content in the first region  181  and display the menu in the second region  182 . In this instance, the menu may be displayed without hiding the first content and the height of the first content may be adjusted. 
     Next,  FIGS.  9 A to  9 C  are diagrams illustrating a method of displaying a menu in a region of a display device withdrawn in a height direction according to a second embodiment of the present invention. As shown in  FIG.  9 A , the display unit  180  can include a first region  181  and first content can be displayed in the first region  181 . When a menu display command is received, the controller  170  can withdraw the display unit  180  in the height direction to add a second region  182  as shown in  FIG.  9 B . 
     As shown in  FIG.  9 C , the second region  182  may be located above the first region  181 . That is, even when the display unit  180  is withdrawn, the location of the first region  181  may be fixed and the second region  182  may be added to the upper side of the first region  181 . Accordingly, the first content can be displayed at the fixed location of the first region  181  and the menu can be displayed while rising from the upper surface of the first content. 
     In this instance, the menu can be displayed without hiding the first content. That is, the menu can be displayed in a separate region while displaying the first content at the fixed location, such that the user views the content without interruption. 
       FIG.  6 A  will be described again. The controller  170  can sense whether an item selection command displayed in the menu is received (S 19 ). When a command for selecting any one of at least one item displayed in the menu is received, the controller  170  can display second content corresponding to the selected item in the first region  181  or the second region  182  (S 21 ). 
     Next, a method of displaying content corresponding to an item selected from a menu in a first region according to various embodiments of the present invention will be described with reference to  FIGS.  10 A to  10 C , a method of displaying content corresponding to an item selected from a menu in a second region according to a first embodiment of the present invention will be described with reference to  FIGS.  11 A and  11 B , and a method of displaying content corresponding to an item selected from a menu in a second region according to a second embodiment of the present invention will be described with reference to  FIGS.  12 A and  12 B . 
     First, as shown in  FIG.  10 A , the display unit  180  can display first content in the first region  181  and display a menu in the second region  182 . The controller  170  can receive a command for selecting any one item displayed in the menu. More specifically, the controller  170  can receive a command for selecting any one item displayed in the menu through a pointer  205 . The pointer  205  can be controlled through the remote control device  200  or through a voice command, gesture input, iris recognition, etc. 
     According to the first embodiment of the present invention, the controller  170  can display second content corresponding to the item selected from the menu in the first region  181  as shown in  FIG.  10 B . That is, the display unit  180  can replace the first content displayed in the first region  181  with the second content corresponding to the item selected from the menu. In the second region  182 , the same menu can be continuously displayed. In this instance, the user can manipulate the menu displayed in the second region  182  while checking the second content displayed in the first region  181 . 
     According to the second embodiment of the present invention, the controller  170  can display the second content corresponding to the item selected from the menu in the first region  181  while inserting the display unit  180  so as to reduce the size of the second region  182  as shown in  FIG.  10 C . That is, the controller  170  can reduce the size of the second region  182  to downsize the menu while displaying the second content corresponding to the item selected from the menu in the first region  181 . In this instance, as a specific item is selected from the menu, the unnecessary menu may be simply displayed and the user can concentrate on the content corresponding to the selected item. 
     Next,  FIGS.  11 A and  11 B  are diagrams illustrating a method of displaying content corresponding to an item selected from a menu in a second region according to a first embodiment of the present invention. As shown in  FIG.  11 A , the display unit  180  can display first content in a first region  181  and display a menu in a second region  182   a . The controller  170  can receive a command for selecting any one item from the menu through a pointer  205 . 
     When a command for selecting any one item from the menu is received, the controller  170  can withdraw the display unit  180  to further extend the second region  182   a  as shown in  FIG.  11 B . As the display unit  180  extends, the display unit  180  can include a first region  181 , a second region  182   a  and an extended second region  182   b.    
     The display unit  180  can display first content in the first region  181 , display the menu in the second region  182   a , and display second content corresponding to the item selected from the second region  182   b  in the extended second region  182   b . In this instance, the display device  100  can display the first content such as broadcast video and the second content corresponding to the menu and the item selected from the menu so as not to overlap. The user can simultaneously acquire a variety of information through the extended region as the display unit  180  is withdrawn. 
     Next,  FIGS.  12 A and  12 B  are diagrams illustrating a method of displaying content corresponding to an item selected from a menu in a second region according to a second embodiment of the present invention. As shown in  FIG.  12 A , the display unit  180  can display first content in the first region  181  and display the menu in the second region  182 . The controller  170  can receive a command for selecting any one item from the menu through a pointer  205 . 
     The controller  170  can display the second content corresponding to the item selected from the menu in the second region  182 . That is, as a command for selecting any one item from the menu is received, the display unit  180  can change the second content displayed in the second region  182  to content corresponding to the item selected from the menu. Meanwhile, the second content displayed in the second region  182  may be obtained by downsizing the original content. According to the embodiment shown in  FIGS.  12 A and  12 B , the user can easily perform necessary manipulation through the menu while viewing the first content such as broadcast video without being interrupted by the menu. 
       FIG.  6 A  will be described again. The controller  170  can receive a command for dragging and dropping any one of the first region and the second region  182  to another region (S 23 ). When the command for dragging and dropping any one of the first region  181  and the second region  182  to another region, the controller  170  can exchange the display regions of the first content and the second content (S 25 ). 
     A method of changing a display region of content according to an embodiment of the present invention will be described with reference to  FIGS.  13 A to  13 C . As shown in  FIG.  13 A , the display unit  180  can display first content in the first region  181  and display second content in the second region  182 . The controller  170  can receive a command for selecting one point from the second region  182  to drag and drop the point to the first region  181 . In contrast, the controller  170  can receive a command for selecting one point from the first region  181  to drag and drop the point to the second region  182 . 
     When the drag-and-drop command is received, the controller  170  can exchange the display regions of the first content and the second content. That is, the controller  170  can display the first content displayed in the first region  181  in the second region and display the second content displayed in the second region  182  in the first region  181 . 
     According to one embodiment of the present invention, as shown in  FIG.  13 B , the controller  170  can reduce the size of the first content while maintaining the aspect ratio of the first content displayed in the first region  181 . The controller  170  can display the downsized first content in the second region  182  and display the enlarged second content in the first region  181 . 
     According to another embodiment of the present invention, as shown in  FIG.  13 C , the controller  170  can reduce the aspect ratio of the first content displayed in the first region  181  to correspond to that of the second region  182 . The controller  170  can display the downsized first content in the second region  182  and display the enlarged second content in the first region  181 . 
     The display device  100  according to the embodiment of the present invention may easily change the locations of the first content and the second content respectively displayed in the first region  181  and the second region  182  through the drag-and-drop command. The user can conveniently enlarge and view specific content. 
       FIG.  6 A  will be described again. The controller  170  can receive a connection signal of a first external device (S 27 ). Here, the first external device may be a device connected to the display device  100  through the external device interface  135 . For example, the first external device may be a mobile terminal such as a smartphone, a game console, a tablet PC, a DVD player, a set-top box, etc., as an example. The first external device may include all devices connectable to the display device  100 . 
     When the connection signal of the first external device is received, the controller  170  can withdraw the display unit  180  to add the second region  182  (S 29 ). The display unit  180  can display information on the first external device in the second region  182  (S 31 ). Here, the information on the external device may be second content and the connection signal of the external device may be a second content display command. 
     Next, a method of displaying content upon connection with an external device according to a first embodiment of the present invention will be described with reference to  FIGS.  14 A to  14 C . Referring to  FIG.  14 A , the display unit  180  can display first content such as broadcast video in the first region  181 . The controller  170  can receive the connection signal of the first external device  300  while displaying the first content. When the connection signal of the first external device  300  is received, the controller  170  can withdraw the display unit  180  to add the second region  182  and display information on the first external device  300  in the second region  182 . 
     The display unit  180  can be withdrawn in a vertical direction as shown in  FIG.  14 B  or in a horizontal direction as shown in  FIG.  14 C  based on device information or connection information of the first external device  300 . According to one embodiment of the present invention, as shown in  FIG.  14 B , the display unit  180  can be withdrawn in the vertical direction and information related to the first external device  300  can be displayed in the second region  182 . Here, the information related to the first external device  300  may include file information such as photos, video, music, web addresses, etc. stored in the first external device  300  and information on functions which may be performed through the first external device  300 . 
     According to another embodiment of the present invention, as shown in  FIG.  14 C , the display unit  180  can be withdrawn in the horizontal direction and a mirroring screen  310  of the first external device  300  can be displayed in the second region  182 . The mirroring screen  310  may mean that the screen of the first external device  300  is displayed on the display device  100 . 
     The controller  170  can receive a command for controlling the mirroring screen  310 , thereby controlling the first external device  300 . In this instance, it is possible to easily manipulate the external device connected to the display device  100  while viewing the first content. 
     Next, a method of displaying content upon connection with an external device according to a second embodiment of the present invention will be described with reference to  FIGS.  15 A and  15 B . Referring to  FIG.  15 A , the display unit  180  can display first content such as broadcast video in the first region  181 . The controller  170  can receive the connection signal of the first external device  300  while displaying the first content. 
     When the connection signal of the first external device  300  is received, the controller  170  can withdraw the display unit  180  to add the second region  182 . More specifically, the controller  170  can withdraw the display unit  180  based on the aspect ratio of the content reproduced through the first external device  300 . 
     The aspect ratio of the content reproduced through the first external device  300  may be different from that of the first content. The controller  170  can withdraw the display unit  180  such that the aspect ratio of the display unit  180  is equal to that of the content reproduced through the first external device  300 . 
     As shown in  FIG.  15 B , the display unit  180  can display the content reproduced through the first external device  300  in the first region  181  and the second region  182 . That is, the display unit  180  can display the content reproduced through the first external device using the first region  181  and the second region  182 . In this instance, the region of the display unit  180  can be optimized according to the aspect ratio of the content reproduced through the external device  300 . 
       FIG.  6 A  will be described again. The controller  170  can receive a connection signal of a second external device (S 33 ). The controller  170  can receive the connection signal of the second external device in a state of connection with the first external device. 
     When the connection signal of the second external device is received in a state of connection with the first external device, the controller  170  can withdraw the display unit  180  to add a third region (S 35 ). The controller  170  can display information on the second external device in the third region (S 37 ). 
     Next, a method of displaying content upon connection with a plurality of external devices according to an embodiment of the present invention will be described with reference to  FIGS.  16 A and  16 B . As shown in  FIG.  16 A , when only the first external device  300   a  is connected, the controller  170  can display first content in the first region  181  and display information on the first external device  300   a  in the second region  182   a . The controller  170  can receive the connection signal of the second external device  300   b  in a state of connection with the first external device  300   a.    
     Referring to  FIG.  16 B , the controller  170  can extend the display unit  180  to add the third region  182   b  as the connection signal of the second external device  300   b  is received. The display unit  180  can display the information on the first external device  300   a  in the second region  182   a  and display the information on the second external device  300   b  in the third region  182   b.    
     Although the number of external devices connected to the display device  100  is 2 in  FIG.  16 B , this is merely exemplary. The display device  100  can simultaneously display the first content such as broadcast video and the information on the connected external device. 
       FIG.  6 A  will be described again. The controller  170  can receive a disconnection signal of any one of the first external device and the second external device (S 39 ). The controller  170  can insert the display unit  180  of a region corresponding to the disconnected external device (S 41 ). 
     Next, a method of inserting a display unit according to disconnection of an external device according to an embodiment of the present invention will be described with reference to  FIG.  16 C . The controller  170  can receive a disconnection signal of any one external device in a state of connection with the first external device  300   a  and the second external device  300   b . The controller  170  can insert the display unit  180  such that the information on the external device corresponding to the received disconnection signal disappears. 
     Referring to  FIG.  16 C , the controller  170  can receive the disconnection signal of the first external device  300   a  in a state of connection with the first external device  300   a  and the second external device  300   b . The controller  170  can insert the display unit  180  to remove the second region  182   a  which is the information display region of the disconnected first external device  300   a . The display device  100  may immediately remove unnecessary information and provide only necessary information to the user while displaying the connection state of the external device. 
       FIG.  6 A  will be described again. The controller  170  can receive a voice command signal (S 43 ). The controller  170  can recognize a predetermined keyword such as recommendation, search, etc. The controller  170  can receive the voice command signal from the user through keyword recognition. 
     The controller  170  can acquire information corresponding to the voice command signal (S 45 ). The controller  170  can search for the information corresponding to the voice command signal based on the recognized keyword. The controller  170  can search for the keyword included in the voice command signal through the network interface  133  or information stored in the memory  140  and acquire the information corresponding to the voice command signal. 
     The controller  170  can withdraw the display unit  180  to add the second region  182  based on the amount of acquired information (S 47 ). The controller  170  can calculate the size of the region for displaying the acquired information. The controller  170  can withdraw the display unit  180  to add the second region  182  by the calculated size of the region. 
     The controller  170  can display information corresponding to the voice command signal in the second region  182  (S 49 ). The controller  170  can display information corresponding to the voice command signal in the second region  182  according to withdrawal of the display unit  180 . 
     Next, a method of displaying content based on a voice command signal according to an embodiment of the present invention will be described with reference to  FIGS.  17 A to  17 D . Referring to  FIG.  17 A , the display unit  180  can display first content such as broadcast video in the first region  181 . 
     Referring to  FIG.  17 B , the controller  170  can receive the voice command signal and withdraw the display unit  180  to add the second region  182  according to the voice command signal. For example, the controller  170  can receive a voice command signal “movie recommendation”. The controller  170  can acquire information corresponding to “movie recommendation”. The controller  170  can calculate the size of the second region  182 , in which the acquired information will be displayed, based on the amount of acquired information. The controller  170  can withdraw the display unit  180  to add the second region  182  having the calculated size. The controller  170  can display information corresponding to the voice command signal in the withdrawn second region  182 . 
     As shown in  FIG.  17 C , the controller  170   b  may further receive another voice command signal in a state of displaying the information corresponding to the voice command signal in the second region  182 . The controller  170  can acquire the information corresponding to the lately received voice command signal and calculate the size of the second region  182  based on the amount of acquired information. The controller  170  can withdraw or insert the display unit  180  based on the calculated size of the second region  182 . More specifically, the controller  170  can further withdraw the display unit  180  when the newly calculated size of the second region  182  is greater than the current size of the second region  182  and insert the display unit  180  when the newly calculated size of the second region  182  is less than the current size of the second region  182 . 
     The controller  170  can completely insert the display unit  180  corresponding to the second region  182  when there is no information to be displayed in the second region  182  as a result of acquiring the information corresponding to the voice command signal based on the received voice command signal. For example, as shown in  FIG.  17 D , the controller  170  can receive a voice command signal “movie  1  playback”, insert the display unit  180  when there is no information to be displayed in the second region  182 , and display content corresponding to the voice command signal in the first region  181 . 
     The display device  100  according to the embodiment of the present invention may adjust the size of the second region  182  according to the voice command signal to withdraw or insert the display unit  180  and display information corresponding to the voice command signal in the second region  182 . 
       FIG.  6 A  will be described again. The controller  170  can sense whether a display-unit withdrawal command is received as shown in  FIG.  6 B  (S 51 ), when the voice command signal is not received. The display-unit withdrawal command may mean a command for withdrawing the display unit  180  in the vertical or horizontal direction to add a new display region in addition to the region in which the content is currently displayed. 
     The display-unit withdrawal command may include a specific-region withdrawal command and a content display command. More specifically, the specific-region withdrawal command may be a command for enabling a user to specify a region to be added of a display unit and the size thereof. The controller  170  can receive the specific-region withdrawal command for setting a withdrawal direction and a withdrawal length and may withdraw the display unit  180  according to the received specific-region withdrawal command. 
     The withdrawal direction may include a vertical direction and a horizontal direction and the withdrawal length may include a plurality of steps. For example, the controller  170  can include a command for withdrawing the display unit in one step in the horizontal direction or a display-unit withdrawal command in three steps in the vertical direction. As the number of steps increases, the withdrawal length may increase. 
     The content display command may be a command for displaying second content in a state of displaying first content in the first region  181 . When a new content display command is received, the controller  170  can withdraw the display unit  180  and display second content in the withdrawn second region  182 . In the present invention, the second content display command may include all commands for displaying content capable of being displayed on the display device  100 , such as a screen setting menu display command, a channel information display command, a time shift execution command, an IOT state display command, a subtitle display command, an aspect-ratio change command, a user setting information display command, a content-related information display command, etc. 
     When the display-unit withdrawal command is received, the controller  170  can withdraw the display unit  180  to add the second region  182  (S 53 ), and the display unit  180  can display the second content in the second region  182  (S 55 ). The location and size of the second region  182  may be changed according to the type of the display-unit withdrawal command. 
     Hereinafter, a method of withdrawing a display unit  180  according to type of a display-unit withdrawal command and displaying second content in a second region  182  added according to withdrawal of the display unit  180  will be described using various examples. 
     Next, a method of displaying content according to a display-unit withdrawal command according to a first embodiment of the present invention will be described with reference to  FIGS.  18 A and  18 B . The controller  170  can receive the display-unit withdrawal command and the display-unit withdrawal command may be a screen setting menu display command. 
     As shown in  FIG.  18 A , when the screen setting menu display command is received, the controller  170  can withdraw the display unit  180  to add the second region  182 . The display unit  180  can display the second content in the second region  182  and the second content may include at least one screen setting item. For example, the screen setting item may include a movie mode setting item  401 , a photo mode setting item  402 , a game mode setting item  403  and a manual setting item  404 . 
     The controller  170  can receive a command for adjusting any one of the screen setting items displayed in the second region  182 . The controller  170  can change the screen mode of the first content displayed in the first region  181  as the command for adjusting any one of the screen setting items is received. 
     For example, referring to  FIG.  18 B , the controller  170  can receive a command for adjusting brightness of the manual setting item  404  displayed in the second region  182  and change brightness of the first content displayed in the first region  181 . The display device  100  may display the screen adjustment result while adjusting the screen mode through the screen setting item displayed in the added second region  182 . The user can easily set the screen mode through the screen adjustment result and the screen setting item respectively displayed in the first region  181  and the second region  182 . 
     Next, a method of displaying content according to a display-unit withdrawal command according to a second embodiment of the present invention will be described with reference to  FIGS.  19 A and  19 B . The controller  170  can receive the display-unit withdrawal command and the display-unit withdrawal command may be a channel information display command. 
     As shown in  FIG.  19 A , when the channel information display command is received, the controller  170  can withdraw the display unit  180  to add the second region  182 . The display unit  180  can display second content in the second region  182  and the second content may include at least one piece of channel information  501 ,  502 ,  503 ,  504  and  505 . The channel information may include at least one of a channel number, a program name and program time information. 
     The controller  170  can receive a command for selecting any one of the channel information  501 ,  502 ,  503 ,  504  and  505  in the second region  182 . When the command for selecting any one of the channel information  501 ,  502 ,  503 ,  504  and  505  is received, the controller  170  can display content corresponding to the selected channel information in the first region  181 . For example, referring to  FIG.  19 B , the controller  170  can receive a command for selecting channel information  501  from among the channel information  501 ,  502 ,  503 ,  504  and  505  through a pointer  203  and display content corresponding to the selected channel information  501  in the first region  181 . 
     The display device  100  can receive a command for selecting any one of the channel information displayed in the second region  182  to immediately display the channel in the first region  181 . The user can easily change the channel through the channel information displayed in the added second region  182 . 
     Next, a method of displaying content based on a display-unit withdrawal command according to a third embodiment of the present invention will be described with reference to  FIG.  20   . The controller  170  can receive the display-unit withdrawal command and the display-unit withdrawal command may be a time shift execution command. 
     As shown in  FIG.  20   , when the time shift execution command is received, the controller  170  can withdraw the display unit  180  to add the second region  182 . The display unit  180  can display second content in the second region  281  and the second content may include time shift execution information. More specifically, the time shift execution information may include at least one of a recorded time shift video  601 , recording information  602  and stored recordings  603  and  604 . 
     The controller  170  can display the first content in the first region  181  and, at the same time, display the time shift execution information in the second region  182 . The user can simultaneously view the first content and the recorded time shift video and control recording of the time shift video. 
     Next, a method of displaying content a display-unit withdrawal command according to a fourth embodiment of the present invention will be described with reference to  FIG.  21   . The controller  170  can receive the display-unit withdrawal command and the display-unit withdrawal command may be an IOT state display command. 
     As shown in  FIG.  21   , when the IOT state display command is received, the controller  170  can withdraw the display unit  180  to add the second region  182 . The display unit  180  can display second content in the second region  182  and the second content may include IOT state information. More specifically, the IOT state information means the state information of an external device connected to the display device  100  and may include information on a washing machine, air conditioner, air purifier, camera, CCTV, etc. connected to the display device  100 . 
     For example, the display unit  180  can display the first content in the first region  181  and display state information  701  of the washing machine connected to the display device  100 , CCTV information  702 , etc. in the second region  182 . The user can check the state of the external device connected to the display device  100  along with the first content such as broadcast video. That is, the user can check the state of the external device while viewing content, without stopping viewing of the content in order to check the state of the external device. 
     Next, a method of displaying content based on a display-unit withdrawal command according to a fifth embodiment of the present invention will be described with reference  FIGS.  22 A and  22 B . The controller  170  can receive the display-unit withdrawal command and the display-unit withdrawal command may be a subtitle display command. 
     According to one embodiment, the subtitle display command may be received through a button provided in the remote control device  200 . According to another embodiment, the subtitle display command may be received as the controller  170  senses a subtitle included in di splayed content. 
     As shown in  FIG.  22 A , the controller  170  can display first content including a subtitle. When the subtitle display command is received, the controller  170  can withdraw the display unit  180  to add the second region  182  as shown in  FIG.  22 B . The display unit  180  can display second content in the second region  182  and the second content may include the subtitle of the first content displayed in the first region  181 . 
     The display unit  180  can display the subtitle in the second region  182  which does not overlap the first content while maintaining the size and aspect ratio of the first content. The user can easily view the subtitle of the first content displayed in a region different from that of the first content along with the first content. 
     Next, a method of displaying content based on a display-unit withdrawal command according to a sixth embodiment of the present invention will be described with reference to  FIGS.  23 A to  24 B . The controller  170  can receive the display-unit withdrawal command and the display-unit withdrawal command may be an aspect-ratio change command. 
     According to one embodiment, the aspect-ratio change command may be received through a button provided in the display unit  180 , the remote control device  200 , etc. According to one embodiment, the aspect-ratio change command may be a content display command having an aspect ratio different from that of the first region  181 . When the content display command is received, the controller  170  can display content in the first region  181 . 
     The aspect ratio of the content corresponding to the content display command may be different from that of the first region  181 . For example, if the content corresponding to the content display command is content having a special aspect ratio (21:9), such as I-MAX video or soccer video, the aspect ratio of the content may be different from that of the first region  181 . The controller  170  can display first content, a portion of which is omitted to suit the aspect ratio of the first region  181 , in the first region  181 . 
     According to one embodiment, as shown in  FIG.  23 A , the display unit  180  can display the first content, an upper or lower portion of which is omitted. When the aspect ratio of the content is recognized, the controller  170  can withdraw the display unit  180  in the vertical direction to add the second region  182  based on the aspect ratio of the content, in order not to omit the portion of the content, as shown in  FIG.  23 B . The controller  170  can display the first content, the portion of which is omitted, in the first region  181  and display the second content, which is the omitted content, in the second region  182 . 
     According to another embodiment, as shown in  FIG.  24 A , the display unit  180  can display the first content, a left or right region of which is omitted. When the aspect ratio of the content is recognized, the controller  170  can withdraw the display unit  180  in the horizontal direction to add the second region  182  based on the aspect ratio of the content, in order not to omit the portion of the content as shown in  FIG.  24 B . The controller  170  can display the first content, the portion of which is omitted, in the first region  181  and display the second content, which is the omitted content, in the second region  182 . 
     The display unit  180  can display the content without omission, when the content display command having the aspect ratio different from that of the first region  181  is received. Meanwhile, the controller  170  can further withdraw the display unit  180  to add a new region, when a display-unit withdrawal command is received in a state of withdrawing the display unit  180 , as described above. 
     Hereinafter, a method of displaying content based on a display-unit withdrawal command will be described with reference to  FIG.  6 B . The controller  170  can sense whether the display-unit withdrawal command is received in a state of adding the second region (S 57 ). When the display-unit withdrawal command is received in a state of adding the second region, the controller  170  can withdraw the display unit  180  to generate a third region (S 59 ), and display third content in the third region (S 61 ). 
     Next, a method of displaying content based on a display-unit withdrawal command according to a seventh embodiment of the present invention will be described with reference to  FIGS.  25 A to  25 C . As shown in  FIG.  25 A , the display unit  180  can display the first content in the first region  181 . The controller  170  can receive a display-unit withdrawal command in a state of displaying the first content and the display-unit withdrawal command may be a user setting information display command. 
     Here, the user setting information display command may mean a command for displaying predetermined content in a region added by withdrawing the display unit  180 . The controller  170  can set display of at least one of public transportation information, road traffic information, weather information, popular news information, stock information and shopping information. The controller  170  can display predetermined content according to a user input command or display the above-described content randomly or in predetermined order. 
     In the example shown in  FIG.  25 B , the controller  170  can withdraw the display unit  180  to add the second region  182   a  according to the user setting information display command and display the second content such as public transportation information in the second region  182   a . As shown in  FIG.  25 C , when a display-unit withdrawal command is received in a state of adding the second region  182   a , the controller  170  can withdraw the display unit  180  to add a third region  182   b . The display unit  180  can display third content in the third region  182   b . The third content may be related to the second content. Alternatively, the third content may not be related to the second content. 
     According to one embodiment, when a display-unit withdrawal command is received in a state of displaying the second content composed of only text in the second region  182   a , the controller  170  can display third content composed of text and an image in the second region  182   a  and the third region  182   b . Here, the third content may indicate the same information as the second content but may be different from the second content in terms of representation format. A predetermined amount of information can be displayed based on the size of the display unit  180 . That is, if the size of the display unit  180  is further increased, a larger amount of information can be displayed. 
     Next, a method of displaying content based on a display-unit withdrawal command according to an eighth embodiment of the present invention will be described with reference to  FIGS.  26 A to  26 C . As shown in  FIG.  26 A , the display unit  180  can display the first content in the first region  181 . The controller  170  can receive a display-unit withdrawal command in a state of displaying the first content and the display-unit withdrawal command may be a content related information display command. 
     Here, the content related information display command may mean a command for displaying information related to content which is currently being displayed in a region added by withdrawing the display unit  180 . When the content related information display command is received, the controller  170  can search for information related to the previously displayed content and perform control to display the searched result on the display unit  180 . 
     As shown in  FIG.  26 B , when the content related information display command is received, the controller  170  can withdraw the display unit  180  to add the second region  182   a . The display unit  180  can display the second content in the second region  182   a  and the second content may be related to the first content which is being displayed in the first region  181 . For example, if the first content is baseball video, the second content may be baseball score information. 
     In addition, as shown in  FIG.  26 C , when the content related information display command is received in a state of adding the second region  182   a , the controller  170  can withdraw the display unit  180  to add a third region  182   b . The display unit  180  can display third content in the third region  182   b  and the third content may be related to the second content which is being displayed in the second region  182   a . For example, if the second content is baseball score information, the third content may be sports related information. 
     Therefore, the display device  100  can provide the user with information related to the content which is currently being displayed step by step. In addition, the display device  100  can display content related information while hiding content which is currently being displayed. The user can easily acquire information related to the content while viewing the content. 
     According to another embodiment, the controller  170  can receive a display-unit withdrawal command in a state of displaying the first content in the first region  181  as shown in  FIG.  27 A . Referring to  FIG.  27 B , when the display-unit withdrawal command is received, the controller  170  can add a second region  182   a  to display information related to the first content. 
     Referring to  FIG.  27 C , when a display-unit withdrawal command is further received in a state of adding the second region  182   a , the controller  170  can add a third region  182   b  and the display unit  180  can display predetermined content described with reference to  FIGS.  25 A to  25 C , such as weather information, in the third region  182   b . Therefore, the display device  100  can display not only information related to the currently displayed content but also external information according to the display-unit withdrawal command. 
     Next, a method of displaying content based on a display-unit withdrawal command according to an eighth embodiment of the present invention will be described with reference to  FIGS.  28 A to  28 C . As shown in  FIG.  28 A , the display unit  180  can display first content in the first region  181 . The controller  170  can receive the display-unit withdrawal command in a state of displaying the first content. 
     Here, the display-unit withdrawal command may include the display-unit withdrawal command described in the first to seventh embodiments. As shown in  FIG.  28 B , the controller  170  can withdraw the display unit  180  to add the second region  182   a  and the display unit  180  can display second content in the second region  182   a . For example, the second content may be a screen setting menu. The user may want to acquire information on a portion of the second content displayed in the second region  182   a.    
     The controller  170  can receive a display-unit withdrawal command for displaying information on the portion of the second content displayed in the second region  182   a . When a pointer  205  is sensed in one region of the second region  182   a , the controller  170  can receive a display-unit withdrawal command for displaying information corresponding to the location of the pointer  205 . 
     As shown in  FIG.  28 C , the controller  170  can withdraw the display unit  180  to add the third region  182   b  and the display unit  180  can display third content, which is information on a portion of the second content, in the third region  182   b . Here, the third content may include help information of the second content. Therefore, the display device  100  can immediately display necessary information of the user in another region and the user can simultaneously view content and necessary information. 
     Next, a method of displaying content based on a display-unit withdrawal command according to a ninth embodiment of the present invention will be described with reference to  FIGS.  29 A to  29 C . The controller  170  can entirely insert the display unit  180 . More specifically, the display unit  180  can be wound on the guide bar and the entire display region of the display unit  180  can be wound on the guide bar. The guide bar may be accommodated in a housing  183  shown in  FIG.  29 A  and the housing  183  may be transparent. However, the housing  183  may be merely exemplary and the display device  100  can not include the housing  183 . 
     As shown in  FIG.  29 A , the entire region of the display unit  180  can be inserted. In particular, when the display device  100  operates in a speaker mode, the display unit  180  can be entirely inserted. The controller  170  can receive an image display command while the display device operates in the speaker mode. The controller  170  can withdraw the display unit  180  when the image display command is received while the display device operates in the speaker mode. 
     More specifically, as shown in  FIG.  29 B , the controller  170  can divide the screen into the first region  181  and the second region  182 , display content corresponding to the image display command in the first region  181 , display an audio controller for controlling the speaker mode in the second region  182 , and, at the same time, withdraw the display unit  180 . 
     When withdrawal of the display unit  180  is finished, as shown in  FIG.  29 C , the display unit  180  can display the content in the first region  181  and the audio controller in the second region  182 . Therefore, the display device  100  can operate in the speaker mode and, at the same time, display the content. The user can control operation the speaker mode and display of the content on one screen. The type of the above-described display-unit withdrawal command and the type of the displayed content are merely exemplary and thus are not limited thereto. 
       FIG.  6 B  will be described again. The controller  170  can sense whether a display-unit insertion command is received (S 63 ). The display-unit insertion command may mean a command for inserting the display unit  180  to remove a region in which the content is currently being displayed. 
     According to one embodiment, the display-unit insertion command may be an insertion command for specifying a region to be removed. In this instance, the controller  170  can receive the display-unit insertion command including information on the region to be removed and insert the display unit  180  to remove the specified region based on region information. 
     According to another embodiment, the display-unit insertion command may be an automatic insertion command. For example, the controller  170  can receive a display-unit insertion command through a button provided in the remote control device  200 . In this instance, the controller  170  can automatically insert the display unit  180 . 
     When the display-unit insertion command is received, the controller  170  can sense whether the content displayed in the second region may be downsized (S 65 ). More specifically, the controller  170  can analyze the content displayed in the second region in a region having a smaller area than the second region. 
     When the content displayed in the second region may be downsized, the controller  170  can insert a portion of the display unit  180  to reduce the size of the second region (S 67 ) and display the downsized content in the downsized second region (S 69 ). When the content displayed in the second region may be downsized, the controller  170  can insert the display unit  180  based on the size of the content to be reduced. That is, the controller  170  can insert a portion of the display unit  180  such that the size of the second region is equal to that of the content to be downsized. 
     Next, an operation method based on a display-unit insertion command according to an embodiment of the present invention will be described with reference to  FIGS.  30 A to  30 C . As shown in  FIG.  30 A , the controller  170  can display first content in the first region  181  and display second content in the second region ( 182 ). When the display-unit insertion command is received, the controller  170  can determine whether the second content may be downsized. 
     The controller  170  can insert a portion of the display unit  180  when the second content may be downsized. As shown in  FIG.  30 B , the display unit  180  can downsize and display the second content in the second region  182  downsized as the portion of the display unit is inserted. In contrast, when the second content may not be downsized, the controller  170  can entirely insert the display unit corresponding to the second region. That is, as shown in  FIG.  30 C , the controller  170  can insert the display unit  180  to remove the second region  182 . 
     Meanwhile, when the display-unit insertion command is received, the controller  170  can insert the display unit to remove the second region  182  in order shown in  FIGS.  31   a  to  31   c   , regardless of whether the content may be downsized. Therefore, the display device  100  can downsize and remove an unnecessary content display region step by step. 
       FIG.  6 B  will be described again. When the display-unit insertion command is not received, the controller  170  can sense whether a viewing-mode entrance command is received (S 71 ). Here, the viewing-mode entrance command refers to a command for intensively displaying the content displayed in the first region  181 , and content displayed in the region other than the first region  181  may be minimized. 
     According to one embodiment, the controller  170  can receive a viewing-mode entrance command through the button displayed in the remote control device  200  or the menu. According to another embodiment, the controller  170  can receive the viewing-mode entrance command upon sensing that an input signal is not received for a predetermined time. 
     When the viewing-mode entrance command is received, the controller  170  can display predetermined content in the second region  182  (S 73 ). The controller  170  can predetermine content to be displayed in the second region  182  as the viewing-mode entrance command is received. According to one embodiment, the controller  170  can set content to be displayed in the second region  182  by default. According to another embodiment, the controller  170  can set the content to be displayed in the second region  182  through a user input command. 
     Next, a method of displaying content based on a viewing-mode entrance command according to a first embodiment of the present invention will be described with reference to  FIGS.  31 A to  31 C . Referring to  FIG.  31 A , the display unit  180  can display first content in the first region  181  and display second content in the second region  182 . 
     The controller  170  can receive the viewing-mode entrance command. For example, when the input signal is not received for the predetermined time, the controller  170  can receive the viewing-mode entrance command when the input signal is not received for the predetermined time. 
     As shown in  FIG.  31 B , when the input signal is not received for the predetermined time, the controller  170  can display predetermined content in the second region  182 . The predetermined content may include one or more of a current time, a current weather, and viewing information of the user. 
     When a user input signal is sensed in a state of displaying the predetermined content according to the viewing-mode entrance command, the controller  170  can display the second content again in the second region as shown in  FIG.  31 C . Here, the second content may be content displayed before displaying the predetermined content or content corresponding to the user input signal. 
     Next, a method of displaying content based on a viewing-mode entrance command according to a second embodiment of the present invention will be described with reference to  FIGS.  32 A to  32 C . Referring to  FIG.  32 A , the display unit  180  can display first content in the first region  181  and display second content in the second region  182 . The controller  170  can receive the viewing-mode entrance command. For example, when an input signal is not received for a predetermined time, the controller  170  can receive the viewing-mode entrance command. 
     As shown in  FIG.  32 B , when the input signal is not received for the predetermined time, the controller  170  can downsize and display the second content displayed in the second region  182 . The controller  170  can enlarge and display the first content in the region other than the region in which the downsized second content is displayed. 
     The controller  170  can further receive the viewing-mode entrance command in a state of downsizing and displaying the second content. In this instance, the controller  170  can remove the second content and enlarge the first content in the first region  181  and the second region  182 . According to the above-described embodiment, the display device  100  can reduce power consumed to insert the withdrawn display unit  180  again. In addition, the content is displayed in the withdrawn region of the display unit, without wasting the region of the display unit. 
     Meanwhile, according to another embodiment, when the viewing-mode entrance mode is received, the controller  170  can insert the display unit  180  to remove the second region  182 . In this instance, the second region  182  may be removed without user manipulation and thus the user can concentrate on the first content. 
       FIG.  6 B  will be described again. The controller  170  can sense whether a power off command is received (S 75 ). When the power off command is received or when the content displayed in the second region cannot be downsized upon receiving the display-unit insertion command, the controller  170  can entirely insert the display unit corresponding to the second region  182  (S 77 ). Therefore, the display device  100  can remove the unnecessary second region  182 . The user can withdraw or insert the display unit  180  as necessary. 
     According to an embodiment, the above-described method can also be embodied as computer readable codes on a computer readable recording medium. The computer readable recording medium is any data storage device that can store data which can be thereafter read by a computer system. Examples of the computer readable recording medium include read-only memory (ROM), random-access memory (RAM), CD-ROMs, magnetic tapes, floppy disks, and optical data storage devices. 
     As can be seen from the foregoing, the video display device in accordance with the embodiments are not limited to the configuration and method of the embodiments described above, but all or some components of the embodiments may be configured to be selectively combined such that various modifications of the embodiments can be implemented.