Abstract:
An image printing device using a display device according to an embodiment of the present invention comprises: a light collecting device for substantially focusing light output from the display device on a screen of the display device in a vertical direction; and a photographic paper which is located on the light collecting device and is photosensed by light provided from the display device through the light collecting device so that an image displayed on the display device is formed, wherein movement of the photographic paper provided in the image printing device is controlled by an external control device in which the display device is mounted, so that an image displayed on the display device can be formed in the photographic paper provided in the image printing device.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of International Application No. PCT/KR2014/010281 filed on Oct. 30, 2014, which claims priority to Korean Application No. 10-2013-0130132 filed on Oct. 30, 2013, which applications are incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to an apparatus and method for outputting an image, and more particularly, to an apparatus and method for outputting an image displayed on a screen of a display device. 
       BACKGROUND ART 
       [0003]    A variety of functions have recently been provided in a portable device such as a cellular phone or a smartphone. Particularly, since the portable device is equipped with a built-in digital camera, it may take a picture at any time in any place, and store the picture or transmit the picture to an Internet server or a portable device of another user. Further, the portable device may receive various types of content such as text, images, and videos through a mobile communication network, a wireless Internet, or a short-range communication network, and store the received content. When a user wants the content, the portable device may display the content through its display device. Further, as a camera with a higher resolution and more functions is available in the portable device, the portable device satisfies the user as much as a conventional digital camera. 
         [0004]    With the portable device having the digital camera, the user may display and view a captured image on a screen at any time. Meanwhile, the user may need to print the image on a photographic paper, rather than to display it on a screen. In order to print a captured picture on a photographic paper, although inconvenient, the user should provide a picture file stored in the portable device to a printing shop and get the printing shop to deliver a printed picture to the user, or the user should visit a printing shop and pick up a printed picture at the printing shop in person. 
         [0005]    Recently, photo printers for printing a portable-size picture, such as “LG Pocket Photo®” of LG Electronics and “Polaroid® GL 10” of Polaroid, have been commercialized. However, such a conventional photo printer requires multiple electronic parts including a communication device for communicating with a computer or a portable device, a memory for storing a received photo file, a processor for providing overall control to the printer, and a battery built inside the printer. Additionally, the conventional photo printer needs an ink or a heat transfer device for forming an image on a photographic paper according to the type of the photographic paper. Due to the use of a lot of internal parts, a manufacturing process of the conventional portable photo printer is complex. Due to its large size and great weight, the conventional photo printer is inconvenient to carry. Particularly because the conventional photo printer requires expensive internal electronic parts, the complete product is expensive, which makes it difficult to be widely used. 
       SUMMARY 
       [0006]    An object of the present invention devised to solve the conventional problem is to provide an apparatus and method for facilitating printing of an image displayed on a display device of a portable device. 
         [0007]    Another object of the present invention is to provide an apparatus having a simple structure and method for facilitating printing of an image displayed on a display device of a small-size portable device. 
         [0008]    In an aspect of the present invention, an image printing device using a display device includes a light collector for focusing light output from the display device in a direction substantially perpendicular to a screen of the display device, and a photographic paper which is positioned over the light collector, and on which an image displayed on the display device is formed through exposure to light received from the light collector. An external control device having the display device controls movement of the photographic paper in the image printing device to form the image displayed on the display device on the photographic paper in the image printing device. 
         [0009]    The image printing device includes a light collector for focusing light output from the display device in a direction substantially perpendicular to a screen of the display device, and a photographic paper which is positioned over the light collector, and on which an image displayed on the display device is formed through exposure to light received from the light collector. 
         [0010]    In another aspect of the present invention, a portable device for controlling an image printing device includes a display device for displaying an image to be printed, a communication unit configured to be connected to an interface unit of the image printing device, and a controller for controlling movement of at least one of a photographic paper and a light shutter in the image printing device to form the image displayed on the display device on the photographic paper in the image printing device. 
         [0011]    In another aspect of the present invention, a method for printing an image using a display device includes receiving an image print request through an input unit of a portable device, displaying an image to be printed, on a display device of the portable device, and controlling movement of at least one of a photographic paper and a light shutter in an image printing device connected to the portable device, to form an image displayed on the display device on the photographic paper in the image printing device. 
         [0012]    In another aspect of the present invention, in a non-transitory computer-readable storage medium recording a program, the program performs operations of receiving an image print request through an input unit of a portable device, displaying an image to be printed, on a display device of the portable device, and controlling movement of at least one of a photographic paper and a light shutter in an image printing device connected to the portable device, to form an image displayed on the display device on the photographic paper in the image printing device. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0013]      FIG. 1  is a view illustrating an image printing device using a display device according to an embodiment of the present invention. 
           [0014]      FIGS. 2A, 2B and 2C  are views illustrating exemplary light collectors according to embodiments of the present invention. 
           [0015]      FIG. 3  is a view illustrating an image printing device using a display device according to an embodiment of the present invention. 
           [0016]      FIG. 4  is a view illustrating an external control device according to an embodiment of the present invention. 
           [0017]      FIG. 5  is a front perspective view of an external control device according to another embodiment of the present invention. 
           [0018]      FIG. 6  is a rear perspective view of an external control device according to another embodiment of the present invention. 
           [0019]      FIGS. 7A to 7D  are views illustrating use of an image printing device in connection with a portable device according to embodiments of the present invention. 
           [0020]      FIG. 8  is a flowchart illustrating an operation for printing an image in an image printing device using a display device according to an embodiment of the present invention. 
           [0021]      FIG. 9  is a view illustrating a partial image according to an embodiment of the present invention. 
           [0022]      FIG. 10  is a flowchart illustrating an operation for printing an image in an image printing device using a display device according to another embodiment of the present invention. 
           [0023]      FIG. 11  is a view illustrating a band image according to an embodiment of the present invention. 
           [0024]      FIGS. 12A and 12B  are views explaining a reason for using a band image according to an embodiment of the present invention. 
           [0025]      FIG. 13  is a view illustrating an image printing device using a display device according to another embodiment of the present invention. 
           [0026]      FIG. 14  is a view illustrating an image printing device using a display device according to another embodiment of the present invention. 
           [0027]      FIG. 15  is a view illustrating a moved state of a light shutter in an image printing device using a display device according to another embodiment of the present invention. 
           [0028]      FIG. 16  is a flowchart illustrating an operation for printing an image in an image printing device using a display device according to another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]    Exemplary embodiments of the present invention will be described below in detail with reference to the attached drawings. However, the present invention is not limited or restricted by the exemplary embodiments. Like reference numerals denote components that perform substantially the same functions in the drawings. 
         [0030]    While the ordinal terms such as first or second may be used to describe various components, the components are not limited by the terms. The terms are used only to distinguish one component from another component. For example, a first component may be referred to as a second component, and a second component may be referred to as a first component without departing the scope of the present invention. The terms as used herein are meant for the purpose of describing a specific embodiment, not intended to restrict the present invention. Unless otherwise specified, singular expressions include plural expressions. 
         [0031]      FIG. 1  is a view illustrating an image printing device using a display device according to an embodiment of the present invention. 
         [0032]    Referring to  FIG. 1 , an image printing device  100  according to an embodiment of the present invention includes a light collector  110  and a photographic paper  120 . 
         [0033]    The light collector  110  focuses light output from a display device  210  onto the photographic paper  120 . The light collector  110  focuses light output in a plurality of directions from a screen of the display device  210 , in a direction substantially perpendicular to the screen. In general, light output from the display device  210  travels in a direction parallel to the screen of the display device  210  as well as in the direction perpendicular to the screen. A manufacturer of the display device  210  wants to display an image uniformly on a screen of the display device  210  and also wants a user to be able to clearly view the image displayed on the screen from a direction tilted at a certain angle from the direction perpendicular to the screen as well as from the direction perpendicular to the screen. Accordingly, the display device  210  is generally configured so as to achieve uniform colors and brightness across the entire screen and form a wide angle of view. In the case of a liquid crystal display (LCD), for example, the LCD is equipped with a light diffusion plate and thus diffuses light emitted from a backlight unit in a plurality of directions. In the case of an organic light emitting diodes (OLED) display, the OLED display itself emits light and the emitted light travels in a plurality of directions. The light collector  110  focuses light output in a plurality of directions from the display device  210  onto a surface of the photographic paper  120 . If the light output from the display device  210  is provided directly onto the photographic paper  120  without intervention of the light collector  110 , an image displayed on the display device  210  may be formed blurry and unclear on the photographic paper  120 . In contrast, if the light collector  110  is used, the image displayed on the display device  210  may be formed clear, not blurry on the photographic paper  120 . 
         [0034]    The display device  210  may include a first display area  211  and a second display area  212 . An image that the user wants to be printed is displayed in the first display area  211 . The image displayed in the first display area  211  may be transferred to the photographic paper  120  through the light collector  110 . While the image displayed in the first display area  211  is transferred to the photographic paper  120 , no image may be displayed in the second display area  212 . Also, even though an image is displayed in the second display area  212 , the image displayed in the second display area  212  may not be transferred to the photographic paper  120 . 
         [0035]    The photographic paper  120  is placed on the light collector  110 . As the photographic paper  120  is exposed to light incident from the display device  210  through the light collector  110 , an image displayed on the display device  210  is formed on the surface of the photographic paper  120 . For example, the photographic paper  120  may be an instant camera film such as Fujifilm Instax® or PX100 and PX600 of Impossible Project. A plurality of photographic papers  120  may be stacked in a single cartridge and discharged outside of the cartridge one by one, when used. 
         [0036]    The image printing device  100  may further include a light shutter  130 . The light shutter  130  is arranged in parallel to the light collector  110  and covers the second display area  212  of the display device  210 . Therefore, the light shutter  130  may block light from the area  212  other than the first display area  211  that displays an image to be printed. Black or a part of the image to be printed may be displayed in the second display area  212 . If the photographic paper  120  is provided to be inserted in a cartridge, the cartridge may function as the light shutter  130  because the cartridge may block light output from the second display area  212  other than the first display area  211  displaying an image to be printed from reaching the photographic paper  120 . 
         [0037]      FIGS. 2 a , 2 b  and 2 c    are views illustrating exemplary light collectors according to embodiments of the present invention.  FIG. 2 a    illustrates an example in which the light collector  110  is configured as a linear lens  111 . The linear lens  111  is disposed on the display device  210  and transfers light corresponding to an image displayed on the display device  210  onto the photographic paper  120 . The linear lens  111  is extended in a direction, for example, a second direction  12 , perpendicular to a movement direction of the photographic paper  120 , for example, a first direction  11 . 
         [0038]      FIGS. 2 b  and 2 c    illustrate examples in which the light collector  110  is configured as vertical filters  112  and  113 , respectively. The vertical filters  112  and  113  are disposed on the display device  210  and transfer light corresponding to an image displayed on the display device  210  onto the photographic paper  120 .  FIG. 2 b    illustrates the vertical filter  112  that is a light angle-blocking type. The vertical filter  112  blocks light incident at an angle other than that perpendicular to a screen of the display device  210 , out of light output from the display device  210  by means of grids  21  for blocking viewing angle. The grids  21  may be spaced from one another by, for example, 10 μm˜100 μm.  FIG. 2 c    illustrates the vertical filter  113  that is a microlens type. The microlens-type vertical filter  113  may focus light output from the display device  210  onto the photographic paper  120  by means of a plurality of microlenses  22 , so that an image displayed on the display device  210  may be formed appropriately, not blurry on the photographic paper  120 . 
         [0039]      FIG. 3  is a view illustrating an image printing device using a display device according to an embodiment of the present invention. 
         [0040]    Referring to  FIG. 3 , the image printing device  100  may further include a roller  140  for moving the photographic paper  120 , a motor  142  for rotating the roller  140 , and an interface unit  150  for providing the motor  142  with a control command for controlling to drive the motor  142 , received from an external control device (not shown) having the display device  210 . The roller  140  and the motor  142  are an exemplary carrying device for carrying the photographic paper  120 . If the image printing device  100  is connected to an external control device  200  through the interface unit  150  so that they may communicate with each other, an on/off operation of the motor  142  may be controlled by the external control device  200 . 
         [0041]    The image printing device  110  may further include a voltage control module (not shown) for controlling the magnitude of a control voltage applied to the motor  142  through the interface unit  150 . 
         [0042]    The interface unit  150  may include a connector for direct connection to the external control device by cable (for example, a universal serial bus (USB) port or a dedicated port), or a short-range communication module for wireless connection to the external control device by wireless short-range communication. The external control device may be a portable communication device such as a smartphone or a cellular phone, or any portable device equipped with a display device, such as a digital camera or a vehicle black box. Accordingly, the interface unit  150  may be a wired or wireless interface for providing a control command received from the external control device to the motor  142 . 
         [0043]    An operation for printing an image on the photographic paper  120  in the image printing device  100  may be controlled by the external control device. Therefore, an independent microprocessor may not be provided in the image printing device  100 . A memory may not be provided in the image printing device  100  either. The image printing device  100  may receive a driving voltage from the external control device. Thus, a battery may not be provided in the image printing device  100 . Accordingly, the image printing device  100  does not need a complex device such as an application processor (AP) or a digital signal processor (DSP), is simplified in structure, and is readily fabricated. Consequently, a cheap printing device may be provided. Obviously, the image printing device  100  may further include at least a part of the microprocessor, the memory, and the battery according to implementation of the image printing device  100 . For example, if the interface unit  150  is configured as a wireless short-range communication module, the image printing device  100  may include a battery for supplying power to the short-range communication module, a motor, and a lamp. For example, if the interface unit  150  is configured as a near field communication (NFC) chip, the NFC chip may include a simple program for an on/off operation of the motor  142 . In this case, a memory may not be provided in the image printing device  100 . 
         [0044]      FIG. 4  is a view illustrating an external control device according to an embodiment of the present invention,  FIG. 5  is a front perspective view of an external control device according to another embodiment of the present invention, and  FIG. 6  is a rear perspective view of an external control device according to another embodiment of the present invention. 
         [0045]    Referring to  FIGS. 4, 5 and 6 , the external control device  200  may include the display device  210 , an input unit  220 , a camera unit  230 , a wireless communication unit  240 , a storage  250 , a power supply  260 , a connector unit  270 , and a controller  280 . Depending on implementation, two or more components may be integrated into one component or a single component may be separated into two or more components in the external control device  200 .  FIGS. 5 and 6  illustrate an example in which the external control device  200  is a portable device. The following description is given in the context of the external control device  200  being a portable device, by way of example. 
         [0046]    The display device  210  displays an image received from the camera unit  230  or the wireless communication unit  240  or an image stored in the storage  250  in the external control device  200 . The image is a picture, a figure, text, or a combination of them, and includes various types of images displayable on the display device  210 . Also, the display device  210  may display various types of information processed in the portable device  200 . For example, if the portable device  200  is operated in a call mode, the display device  210  displays a user interface (UI) or graphic user interface (GUI) related to a call. Meanwhile, if the display device  210  and a touch pad are layered into a touch screen, the display device  210  may be used as an input device as well as an output device. Thus, the input unit  220  may be configured in the display device  210 , and the user may input an intended user command to the display device  210  by touching a key or button formed in the display device  210 . 
         [0047]    The input unit  220  generates key input data that the user inputs to control an operation of the portable device  200 . The input unit  220  may include a key pad, a dome switch, a (resistive or capacitive) touch pad, a jog wheel, a jog switch, or the like. Particularly if a touch pad is layered with the display device  210 , the touch pad and the display device  210  form a touch screen. Also, the input unit  220  may include a microphone for receiving a voice command from the user, and a sensor for sensing a user command input by a user gesture, such as an infrared sensor, a proximity sensor, or an ultrasonic sensor. If a user gesture is input through the camera unit  230 , the camera unit  230  may be incorporated in the input unit  220 , functioning as the input unit  220 . 
         [0048]    The camera unit  230  captures an external object and provides the captured image of the external object. The image provided by the camera unit  230  may be displayed on the display device  210  or stored in the storage  250 . The camera unit  230  may be formed on at least one of the front and rear surfaces of the portable device  200 . 
         [0049]    The wireless communication unit  240  may include a short-range communication module  241 , a mobile communication module  242 , and a wireless Internet module  243 . The short-range communication module  241  performs short-range communication with the image printing device  100  according to an embodiment of the present invention. The short-range communication may be conducted by NFC, wireless fidelity Direct (Wi-Fi Direct), Bluetooth, infrared data association (IrDA), radio frequency identification (RFID), ultra wideband UWB), ZigBee, or the like. The mobile communication module  242  transmits and receives wireless signals to and from at least one of a base station, an external terminal, and a server over a mobile communication network. The wireless signals may include a voice call signal, a video call signal, or various types of data according to transmitting and receiving text/multimedia messages. The wireless Internet module  243  is used for wireless Internet connectivity, and may reside inside or outside the portable device  200 . 
         [0050]    The storage  250  may store an image to be printed by the image printing device  100  and a program for processing and controlling by the controller  280 . The storage  250  may execute a function of temporarily storing input/output data. 
         [0051]    The power supply  260  supplies power for operation of the portable device  200 . Also, the power supply  260  may supply power for operation of the image printing device  100  to the image printing device  100  under control of the controller  280 . 
         [0052]    The connector unit  270  may be used as an interface for enabling the portable device  200  to conduct data communication with an external device or connecting the portable device  200  to an external power source. For example, as the connector unit  270  is connected to a USB port or a cable of the image printing device  100 , the controller  280  may control an operation of the image printing device  100 . The connector unit  270  may be referred to as a wired communication unit. 
         [0053]    The controller  280  provides overall control to the portable device  200 . Further, the controller  280  provides overall control to the image printing device  100  according to embodiments of the present invention. The controller  280  may also control output of a voice notification explaining an image printing method of the image printing device  100  through a speaker  290 . 
         [0054]      FIG. 5  illustrates an example in which the display device  210  is configured as a touch screen. Referring to  FIG. 5 , the display device  210  includes the first display area  211  for displaying an image to be printed. The first display area  211  may be formed at a position facing the photographic paper  120 , when the portable device  200  is engaged with the image printing device  100 . The display device  210  may further include a preview area  510 , a shutter button  520 , a gallery button  530 , and a print button  540 . For example, the shutter button  520 , the gallery button  530 , and the print button  540  may be formed as icons. The preview area  510  may display an image detected by an image sensor of the camera unit  230  so that the image may be previewed. When the shutter button  520  is touched by the user, the controller  280  captures an image displayed in the preview area  510 , determining that a command for capturing an external object displayed in the preview area  510  has been received. When the gallery button  530  is touched by the user, the controller  280  may display pictures pre-stored in the storage  250  on the display. When the print button  540  is touched by the user, the controller  280  controls the image printing device  100  to make the image displayed in the printing image display area  211  formed on the photographic paper  120  inside the image printing device  100 . Along with operation of the image printing device  100 , the controller  280  may determine whether to display an image in the first display area  211 , and control an image to be displayed and a time when the image is to be displayed. For example, at least a part of an original image may be displayed mirrored in the first display area  211  that displays the image to be printed. Since the photosensitive surface of the photographic paper  120  faces the screen of the display device  210 , the original image should be mirrored on the screen of the display device  210  in order to form the original image on the photographic paper  120 . Also, for example, a part of the original image may be displayed in the first display area  211 , or a band image formed based on a part of the original image may be displayed mirrored in the first display area  211 . The band image will be described below in detail. 
         [0055]      FIGS. 7 a  to 7 d    are views illustrating use of an image printing device in conjunction with a portable device according to embodiments of the present invention. 
         [0056]    Referring to  FIG. 7 a   , the portable device  200  may be inserted into a slot  180  formed on a side surface of the image printing device  100 . As illustrated in  FIG. 7 a   , when a bottom end portion of the portable device  200  is inserted into the slot  180 , the connector unit  270  formed at a bottom end of the portable device  200  may be coupled with the interface unit  150  formed in the image printing device  100 . Thus, the portable device  200  may control the image printing device  100  through the interface unit  150 . The portable device  200  may also supply power to the image printing device  100  through the interface unit  150 . Guides  190  may further be formed in the image printing device  100 , for guiding the connector unit  270  of the portable device  200  inserted into the slot  180  to a position at which the interface unit  150  of the image printing device  100  is formed. The guides  190  may support the portable device  200 , in contact with one or both side surfaces of the portable device  200 , so that the portable device  200  may be fixed in the slot  180 . Elastic members  191  may be additionally formed in the image printing device  100 , for providing elasticity to the guides  190 . When a relatively large portable device  200  is inserted into the slot  180  of the image printing device  100 , the elastic members  191  provide elasticity to the guides  190  so that the guides  190  may retreat, guiding the portable device  200  to be appropriately inserted into the slot  180 . Thus, the portable device  200  may be supported fixedly in the slot  180 . Accordingly, the portable device  200  of any of various sizes may be stably engaged with the image printing device  100 . 
         [0057]      FIG. 7 b    illustrates discharge of the photographic paper  120  from the image printing device  100  according to an embodiment of the present invention. Referring to  FIG. 7 b   , the image printing device  100  includes a cover  182  for placing the photographic paper  120  inside the image printing device  100 , and a discharge outlet  184  for discharging the photographic paper  120 . The cover  182  may be configured to be opened or closed or may be detachably formed in the image printing device  100 . The controller  280  discharges the photographic paper  120  from the image printing device  100  after a predetermined time during which the image displayed in the first display area  211  of the display device  210  in the portable device  200  is printed on the photographic paper  120 . A power lamp  186  and a print indication lamp  188  may be additionally installed on an exterior case of the image printing device  100 . When the portable device  200  is coupled with the interface unit  150  of the image printing device  100 , the power lamp  186  may be turned on. The print indication lamp  188  may be kept on during image printing in the image printing device  100  under the control of the portable device  200 , thereby indicating image printing is in progress to the user. The lamps  186  and  188  may be turned on by a voltage applied from the portable device  200 . If the image printing device  100  includes a battery, the lamps  186  and  188  may be turned on by means of the battery. 
         [0058]      FIG. 7 c    illustrates use of an image printing device in conjunction with a portable device according to another embodiment of the present invention. Referring to  FIG. 7 c   , the portable device  200  may be inserted into the slot  180  formed on a side surface of the image printing device  100 . The slot  180  may be opened from its bottom and have catching portions  181  along both end portions of the slot  180 . Therefore, the portable device  200  may be slidingly inserted into the slot  180  or inserted into the slot  180  from under the image printing device  100 . The catching portions  181  may be elastic to appropriately insert the portable device  200 . In the illustrated case of  FIG. 7 c   , the image printing device  100  may be connected to the portable device  200  so that they may communicate with each other by wireless short-range communication. As illustrated in  FIG. 7 d   , the interface unit  150  of the image printing device  100  may include a connector  151  and a cable  152 . The image printing device  100  may be connected to the portable device  200  by using the connector  151  and the cable  152 . 
         [0059]      FIG. 8  is a flowchart illustrating an operation for printing an image in an image printing device using a display device according to an embodiment of the present invention. 
         [0060]    First of all, when the user connects the image printing device  100  to the portable device  200  and then inputs an image print request for an image displayed on the display device  210  through the input unit  220 , the controller  280  of the portable device  200  receives the image print request in operation S 801 . The image requested for printing may be an image pre-stored in the storage  250  of the portable device  200  or an image input to the portable device  200  in real time through the camera unit  230 . For example, as a predetermined part of the portable device  200 , for example, a bottom end portion of the portable device  200  is inserted into the slot  180  of the image printing device  100 , the interface unit  150  formed in the image printing device  100  is inserted into the connector unit  270  of the portable device  200 . Thus, the image printing device  100  may be connected to the portable device  200  so that they may communicate with each other. Also, the portable device  200  may be connected to the image printing device  100  through the interface unit  150  wirelessly or wiredly, so that they may communicate with each other. When the image printing device  100  is connected to the portable device  200  in this manner, the first display area  211  of the display device  210  in which an image to be printed is displayed in the portable device  200  may face the photosensitive surface of the photographic paper  120  in the image printing device  100 . Hereinafter, the image requested for printing will be referred to as an original image. 
         [0061]    Then, the controller  280  subjects the original image to color conversion according to the characteristics of the display device  210 . If the display device  210  is configured as, for example, an LCD or OLED display, the photosensitive characteristics of the photographic paper  120  may vary according to the light emitting type of the display device  210 . Therefore, color conversion is performed by converting pixel data in such a manner that the image may be sensitized naturally on the photographic paper  120  according to the light emitting type of the display device  210 , and thus the original image may be formed appropriately on the photographic paper  120 . In operation S 802 , the original image may be displayed with its brightness inverted on the display device  210  according to the characteristics of the photographic paper  120 . For example, in the case where the pixel values of the original image are 0 to 255, if the brightness of one point in the original image is ‘0’ representing dark, a pixel data for displaying the point on the display device  210  may be set to ‘255’ representing bright. On the contrary, if the brightness of one point in the original image is ‘255’ representing bright, a pixel data for displaying the point on the display device  210  may be set to ‘0’ representing dark. The color conversion operation S 802  is optional and thus may be skipped. 
         [0062]    The controller  280  divides the original image requested for printing into a plurality of partial images each having a predetermined size, and displays a first partial image (for example, a partial image at the top end) out of the partial images on the display device  210  in operation S 803 . The partial images may be obtained by slicing the original image in a horizontal direction. The horizontal direction is a direction perpendicular to a movement direction of the photographic paper  120 . Therefore, the movement direction of the photographic paper  120  may be referred to as a vertical direction. For example, if the original image includes m×n pixels (m and n are integers), each partial image may include one or more consecutive rows from among the pixels of the original image. If the original image is displayed rotated at 90 degrees on the display device  210 , each image line may be a partial image with one or more consecutive columns from among the pixels of the original image. The partial images may include different parts of the original image, and when the partial images are successively concatenated, the original image may be formed. For example, referring to  FIG. 9 , an original image  910  may be divided into a plurality of partial images  920 . Each partial image  920  is formed with one or more consecutive rows from among the pixels of the original image  910 . Accordingly, the partial images  920  may be formed by slicing the original image  910  into a plurality of partial images  920 . 
         [0063]    A predetermined time after the first partial image of the original image is displayed on the display device  210  in operation S 803 , the controller  280  moves the photographic paper  120  for a predetermined distance in operation S 804 . A predetermined time during which the photographic paper  120  is exposed to the display device  210  may vary with the brightness of the display device  210 . For example, if the display device  210  is bright, the predetermined time may be relatively short. On the other hand, if the display device  210  is dark, the predetermined time may be long relative to the case when the display device  210  is bright. The predetermined distance for which the photographic paper  120  is moved corresponds to the width of each partial image. That is, if the partial image is narrow, the predetermined distance is small, and if the partial image is wide, the predetermined distance is large. Also, the controller  280  may control constant movement of the photographic paper  120  at a predetermined velocity. Therefore, the controller  280  may control sequential display times of the partial images in correspondence with the velocity of the photographic paper  120 . 
         [0064]    Subsequently, the controller  280  determines whether the plurality of partial images of the original image have all been displayed on the display device  210  in operation S 805 . 
         [0065]    If all of the partial images of the original image are not displayed on the display device  210  in operation S 805 , the controller  280  returns to operation S 803  in which the next partial image is displayed on the display device  210  and repeats operation S 804  in which the photographic paper  120  is moved for the predetermine distance. As the plurality of partial images of the original image are sequentially displayed on the display device  210  and the partial images are successively concatenated on the photographic paper  120 , the original image may be formed on the photographic paper  120 . 
         [0066]    If it is determined that all of the plurality of partial images of the original image have been displayed on the display device  210 , the controller  280  discharges the photographic paper  120  outside of the image printing device  100  in operation S 806 . 
         [0067]      FIG. 10  is a flowchart illustrating an operation for printing an image in an image printing device using a display device according to another embodiment of the present invention. 
         [0068]    Upon receipt of an image print request for an image displayed on the display device  210  through the input unit  220  of the portable device  200  after the user connects the image printing device  100  to the portable device  200 , the controller  280  of the portable device  200  receives the image print request in operation S 1001 . The portable device  200  may be connected to the image printing device  100  through the interface unit  150  wirelessly or wiredly so that the portable device  200  may communicate with the image printing device  100 . 
         [0069]    Then, the controller  280  subjects the original image requested for printing to color conversion according to the characteristics of the display device  210  in operation S 1002 . The color conversion operation S 1002  is optional and thus may be skipped. 
         [0070]    The controller  280  forms band images out of the original image requested for printing in operation S 1003  and displays the band images on the display device  210  in operation S 1004 . The band images may be displayed mirrored on the display device  210 .  FIG. 11  is a view illustrating an operation for generating a band image according to an embodiment of the present invention. Referring to  FIG. 11 , for example, if the original image  910  is comprised of m×n pixels (m and n are integers), a line image  911  corresponding to an image of each row arranged in a direction perpendicular to the movement direction of the photographic paper  120  is repeatedly copied and then a band image  930  is generated by concatenating the copied line images  911 . The band image  930  includes a plurality of (for example, 10 to 50) identical line images  911 . Therefore, the band image  930  takes the form of the line image  911  stretched in the movement direction of the photographic paper  120 . The band image  930  may have a predetermined width d 1 . The width d 1  may be set to be larger than the width d 2  of the light collector  110  in consideration of the gap between the image printing device  100  and the portable device  200 . For example, if the light collector  110  is configured as a linear lens, the width d 1  may be larger than the size of the linear lens. 
         [0071]      FIG. 12A  illustrates an ideal position  31  for the light collector  110  in the image printing device  100 , when the band image  930  is displayed on the display device  210  in the portable device  200 . The light collector  110  is preferably arranged in parallel to the band image  930 . However, since the image printing device  100  is detachably mounted to the portable device  200 , each time the image printing device  100  is connected to the portable device  200 , the positions of the image printing device  100  and the portable device  200  may be changed slightly due to the gap between the image printing device  100  and the portable device  200 . Therefore, the light collector  110  of the image printing device  100  and the display device  210  of the portable device  200  may not be disposed at the ideal position  31 .  FIG. 12B  illustrates a case in which when the band image  930  is displayed on the display device  210 , an actual position  32  of the light collector  110  is deviated from the ideal position  31  by θ. If each line image  911  of the original image  910  is formed on the photographic paper  120  using the band image  930 , the line image  910  may be formed appropriately on the photographic paper  120 . That is, even though the light collector  100  is slightly out of focus, the light collector  100  may be positioned over the band image  930 . As a consequence, each line image  911  may be formed on the photographic paper  120 . 
         [0072]    A predetermined time after the band image  930  formed using the line image  911  corresponding to the first row of the original image  910  is displayed on the display device  210 , the controller  280  moves the photographic paper  120  for a predetermined distance in operation S 1005 . The predetermined distance for which the photographic paper  120  is moved corresponds to the width of the line image  911 . That is, if the line image  911  is narrow, the predetermined distance is small, and if the line image  911  is wide, the predetermined distance is large. Also, the controller  280  may control constant movement of the photographic paper  120  at a predetermined velocity in operation S 1005 . Accordingly, the controller  280  may control sequential display of each band image  930  according to the velocity of the photographic paper  120 . 
         [0073]    Subsequently, the controller  280  determines whether all of band images  930  corresponding to all line images  911  of the original image have been displayed on the display device  210  in operation S 1006 . 
         [0074]    If all of the band images  930  corresponding to the plurality of line images  911  of the original image have not been displayed on the display device  210 , the controller  280  returns to operation S 1003  in which the controller  280  forms a band image  930  corresponding to the next line image  911 , and repeats operation S 1004  in which the controller  280  displays the band image  930  on the display device  210 , and operation S 1005  in which the controller  280  moves the photographic paper  120  for the predetermined distance. As the band images  930  corresponding to the plurality of line images  911  forming the original image  910  are sequentially displayed on the display device  210  and the line images  911  are successively concatenated on the photographic paper  120 , the original image  910  may be formed on the photographic paper  120 . 
         [0075]    If it is determined that all of the plurality of line images  911  forming the original image have been displayed on the display device  210  in operation S 1006 , the controller  280  discharges the photographic paper  120  outside of the image printing device  100  in operation S 1007 . 
         [0076]      FIG. 13  is a view illustrating an image printing device using a display device according to another embodiment of the present invention. 
         [0077]    Referring to  FIG. 13 , the image printing device  100  according to another embodiment of the present invention includes the light collector  110  and the photographic paper  120 . 
         [0078]    The light collector  110  focuses light output from the display device  210  of the portable device  200  on the photographic paper  120 . The light collector  110  focuses light output in a plurality of directions from a screen of the display device  210  on the photographic paper  120 . 
         [0079]    The light collector  110  is formed in a size corresponding to the first display area  211  that displays an image to be printed on the display device  210 . A whole original image to be printed may be displayed mirrored in the first display area  21 . The light collector  110  may be configured as a vertical filter or a planar lens. The light collector  110  is positioned over the display device  210  and provides light corresponding to the original image displayed on the display device  210  to the photographic paper  120 . 
         [0080]    The size of an image formed on the photographic paper  120  may be equal to or smaller than the size of an image displayed in the first display area  211  of the display device  210 . The size of an image formed on the photographic paper  120  may be controlled according to the light collector  110 . Accordingly, the size of the photographic paper  120  may be equal to or smaller than the size of an image displayed on the display device  210 . That is, the printing image display  211  for displaying an image to be printed in the display device  210  may be formed to be as large as or larger than the photographic paper  120 . 
         [0081]      FIG. 14  is a view illustrating an image printing device using a display device according to another embodiment of the present invention, and  FIG. 15  is a view illustrating a moved light shutter in an image printing device using a display device according to another embodiment of the present invention. 
         [0082]    Referring to  FIGS. 14 and 15 , the image printing device  100  may further include a first roller  140  for moving the photographic paper  120 , the first motor  142  for rotating the first roller  140 , and the interface unit  150  for providing a signal for controlling the first motor  142 , received from the portable device  200  to the first motor  142 . Also, the image printing device  100  may further include a voltage control module (not shown) for controlling a voltage applied to the first motor  142  through the interface unit  150 . 
         [0083]    Additionally, the image printing device  100  may include a second roller  160  for moving the light shutter  130 , and a second motor  162  connected to the interface unit  150 , for rotating the second roller  160  in response to a control command received from the portable device  200 . The light shutter  130  is disposed between the light collector  110  and the display device  210 . Thus, when the light shutter  130  is closed, the light shutter  130  may block light from the display device  210 . If the image printing device  100  is connected to the external control device through the interface unit  150  so that the image printing device  100  may communicate with the portable device  200 , the external control device  200  may control an on/off operation of the first and second motors  142  and  162 . The image printing device  100  may further include a voltage control module (not shown) for controlling a control voltage applied to the second motor  162  through the interface unit  150 .  FIG. 15  illustrates exposure of the photographic paper  120  to the display device  120  along with movement of the light shutter  130  under the control of the controller  280 . In  FIG. 15 , a full original image may be displayed mirrored in the printing image display area  211  for displaying an image to be printed in the display device  210 . Accordingly, the size of the printing image display area  211  corresponds to the sizes of the light collector  110  and the photographic paper  120 . For example, the size of the printing image display area  211  may be equal to or larger than the sizes of the light collector  110  and the photographic paper  120 . 
         [0084]    The interface unit  150  may include a connector for direct wired connection to the portable device  200  or a short-range communication module for wireless connection to the portable device  200  by short-range communication. Thus, the interface unit  150  may be a wired or wireless interface for providing a control signal received from the portable device  200  to the first motor  142  and the second motor  162 . 
         [0085]      FIG. 16  is a flowchart illustrating an operation for printing an image in an image printing device using a display device according to another embodiment of the present invention. 
         [0086]    Referring to  FIG. 16 , upon receipt of an image print request through the input unit  220  of the portable device  200  after the user connects the image printing device  100  to the portable device  200 , the controller  280  of the portable device  200  receives the image print request in operation S 1601 . The image requested for printing may be an image pre-stored in the storage  250  of the portable device  200  or an image input to the portable device  200  in real time through the camera unit  230 . When the image printing device  100  is engaged with the portable device  200  in this manner, the printing image display area  211  of the display device  210  in which an image to be printed is displayed in the portable device  200  may face the photosensitive surface of the photographic paper  120  in the image printing device  100 . 
         [0087]    Then, the controller  280  subjects an image displayed in the printing image display area  211  to color conversion according to the characteristics of the display device  210  in operation S 1602 . The color conversion operation S 1602  is optional and thus may be skipped. 
         [0088]    The controller  280  exposes the whole photosensitive surface of the photographic paper  120  to the printing image display area  211  by controlling driving of the second motor  162  and thus moving the light shutter  130  in operation S 1603 . 
         [0089]    Subsequently, the controller  280  displays an original image, which is to be printed on the photographic paper  120 , in the first display area  211  of the display device  210  in operation S 1604 . The original image may be displayed mirrored on the display device  210  in operation S 1604 . Before displaying the original image to be printed in the first display area  211  in operation S 1604 , the controller  280  may control the entire first display area  211  to display black, thereby preventing exposure of the photographic paper  120  to unnecessary light. Alternatively, the controller  280  may display the original image to be printed in the first display area  211  before opening the light shutter  130 . Therefore, light output from the first display area  211  of the display device  210  may be provided to the photographic paper  120  through the light collector  110 . 
         [0090]    Then, the controller  280  determines whether a predetermined time sufficient to form the original image displayed in the first display area  211  of the display device  210  on the photographic paper  120  has elapsed in operation S 1605 . Upon expiration of the predetermined time, the controller  280  controls driving of the second motor  162  so that the light shutter  130  may return to its original position in operation S 1606 . As a consequence, light may be blocked from the display device  210  to the photographic paper  120 . 
         [0091]    Then, the controller  280  discharges the photographic paper  120  outside of the image printing device  100  in operation S 1607 . 
         [0092]    Meanwhile, if the photographic paper  120  is provided inserted in a cartridge, the operation S 1603  for opening the light shutter  130  and the operation S 1606  for closing the light shutter  130  may be skipped. 
         [0093]    The method for printing an image using a display device according to embodiments of the present invention may be implemented as computer-readable code in a computer-readable recoding medium. The computer-readable recording medium may be any recoding device that stores data readable by a computer system. Examples of the computer-readable recording medium include read only memory (ROM), random access memory (RAM), compact disk-read only memory (CD-ROM), magnetic tape, floppy disk, optical data storage device, and carrier waves such as transmission over the Internet. In addition, the computer-readable recording medium may be distributed over computer systems connected over a network, and computer-readable codes may be stored and executed in a distributed manner. 
         [0094]    While the invention has been described in detail with reference to the preferred embodiments thereof, the above embodiments are to be construed in all aspects as illustrative and not restrictive. Also, it will be understood by those skilled in the art that various embodiments may be implemented without departing from the spirit and scope of the invention. 
         [0095]    According to an embodiment of the present invention, an apparatus and method for facilitating printing of an image displayed on a display device of a portable device can be provided. 
         [0096]    Further, according to an embodiment of the present invention, an apparatus having a simple structure and method for facilitating printing of an image displayed on a display device of a small-size portable device can be provided. 
         [0097]    According to an embodiment of the present invention, a cheap image printing device, which does not need a complex internal device such as an application processor or a digital signal processor inside it and is easy to fabricate in a simple structure, can be provided.