Abstract:
An method and apparatus are provided. The method includes, at an apparatus, determining a display mode to present content, selecting, based at least in part on the display mode, a display from a display module comprising a plurality of stacked displays, operatively coupled with the apparatus, and presenting at least a part of the content via the display.

Description:
PRIORITY 
       [0001]    This is a continuation application for prior application Ser. No. 13/185,700, filed on Jul. 19, 2011, which claims the benefit under 35 U.S.C. §119(a) of a Korean patent application filed on Aug. 6, 2010, in the Korean Intellectual Property Office and assigned Serial No. 10-2010-0075774, the entire disclosures of which are hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an Active Matrix Organic Light Emitting Diode (AMOLED) display and a method of controlling a display thereof. More particularly, the present invention relates to an AMOLED display and a method of controlling a display thereof that use a cholesteric Liquid Crystal Display (LCD) that can operate in a low power mode or a high picture quality mode. 
         [0004]    2. Description of the Related Art 
         [0005]    Nowadays, as a display used for a mobile terminal or an e-paper, an AMOLED display or a Liquid Crystal Display (LCD) are widely available. More particularly, an LCD is classified as a transmissive LCD, a reflective LCD, or a transflective LCD, according to a display method. 
         [0006]    Because the transmissive LCD uses a backlight, a panel, and a line polarizing plate, the transmissive LCD has a low efficiency backlight, consumes a relatively large amount of current, and has low outdoor visibility. The AMOLED display that displays a screen without using external light has a high optical characteristic, but also consumes a relatively large amount of power. 
         [0007]    The reflective LCD uses external light as a light source using a reflector, a panel, and a circular polarization plate, and has a reflexibility of less than 20%. Thus, the reflective LCD cannot display a screen at a location having a low indoor visibility and having no external light. The reflective LCD uses a cholesteric LCD, and a related art cholesteric LCD is described with reference to  FIG. 1 . 
         [0008]      FIG. 1  is a perspective view illustrating a cholesteric LCD of the related art. 
         [0009]    Referring to  FIG. 1 , a cholesteric LCD  10  includes an absorption layer  11 , a first cholesteric liquid crystal color layer  12  in which a first transparent electrode film  15  is attached to an upper surface thereof, a second cholesteric liquid crystal color layer  13  in which a second transparent electrode film  16  is attached to an upper surface thereof, and a third cholesteric liquid crystal color layer  14  in which a third transparent electrode film  17  is attached to an upper surface thereof. The absorption layer  11 , the first cholesteric liquid crystal color layer  12 , the second cholesteric liquid crystal color layer  13 , and the third cholesteric liquid crystal color layer are sequentially stacked. In the cholesteric LCD  10 , power is required only when a state of one or more of the cholesteric liquid crystal color layers  12 ,  13 , and  14  changes, and thus the cholesteric LCD  10  has bistability, very low power consumption, a low optical characteristic, and a slow response speed. 
         [0010]    The transflective LCD has a portion operating as a reflective LCD and other portions operating as a transmissive LCD by disposing a reflector at a part of a pixel, and has a structure entailing a little lower transmitting characteristic and higher outdoor visibility than that of the transmissive LCD. However, because of the reflector, the transflective LCD has a reduced aperture ratio, resulting in low luminance, and a reduced color reproduction ratio. Further, in order to obtain a desired color reproduction ratio, reflexibility is limited to about 2% to 5%, and therefore it is difficult to apply a high specification of display and to apply AMOLED technology. Further, due to the expansion of the e-book market, a further limitation has become increasingly important in reducing the required power consumption. 
       SUMMARY OF THE INVENTION 
       [0011]    Aspects of the present invention are to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide an Active Matrix Organic Light Emitting Diode (AMOLED) display and a method of controlling a display thereof that can operate as an AMOLED of a high picture quality when used in an indoor environment or when viewing a motion picture, and that can operate as a cholesteric Liquid Crystal Display (LCD) of super low power consumption when used in an outdoor environment or when using as an e-book reader. 
         [0012]    In accordance with an aspect of the present invention, a method is provided. The method includes, at an apparatus, determining a display mode to present content, selecting, based at least in part on the display mode, a display from a display module comprising a plurality of stacked displays, operatively coupled with the apparatus, and presenting at least a part of the content via the display. 
         [0013]    In accordance with another aspect of the present invention, an apparatus is provided. The apparatus includes a display module and a controller. The display module includes a plurality of stacked displays, operatively coupled with the apparatus. The controller is operatively coupled with the display module and configured to determine a display mode to present a content, to select, based at least in part on the display mode, a display from the plurality of stacked displays, and to present at least a part of the content via the display. 
         [0014]    In accordance with yet another aspect of the present invention, a method is provided. The method includes, at an apparatus, determining a display mode based at least in part on an environment of the apparatus or a display operatively coupled with the apparatus, and presenting content via the display or one or more other displays operatively coupled with the apparatus, based at least in part on the display mode. 
         [0015]    Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description in conjunction with the accompanying drawings, in which: 
           [0017]      FIG. 1  is a perspective view illustrating a cholesteric Liquid Crystal Display (LCD) of the related art; 
           [0018]      FIG. 2  is a perspective view illustrating a display unit of an Active Matrix Organic Light Emitting Diode (AMOLED) display according to an exemplary embodiment of the present invention; 
           [0019]      FIG. 3  is a diagram illustrating a low power mode operation of the display unit of  FIG. 2  according to an exemplary embodiment of the present invention; 
           [0020]      FIG. 4  is a diagram illustrating a high picture quality mode operation of the display unit of  FIG. 2  according to an exemplary embodiment of the present invention; 
           [0021]      FIG. 5  is a block diagram illustrating a configuration of an AMOLED display according to an exemplary embodiment of the present invention; and 
           [0022]      FIG. 6  is a flowchart illustrating a method of controlling a display of the AMOLED display of  FIG. 5  according to an exemplary embodiment of the present invention. 
       
    
    
       [0023]    Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures. 
       DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0024]    The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding, but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness. 
         [0025]    The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention is provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents. 
         [0026]    It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more of such surfaces. 
         [0027]      FIG. 2  is a perspective view illustrating a display unit of an Active Matrix Organic Light Emitting Diode (AMOLED) display according to an exemplary embodiment of the present invention,  FIG. 3  is a diagram illustrating a low power mode operation of the display unit of  FIG. 2  according to an exemplary embodiment of the present invention,  FIG. 4  is a diagram illustrating a high picture quality mode operation of the display unit of  FIG. 2  according to an exemplary embodiment of the present invention, and  FIG. 5  is a block diagram illustrating a configuration of an AMOLED display according to an exemplary embodiment of the present invention. 
         [0028]    Referring to  FIGS. 2 and 5 , an AMOLED display according to an exemplary embodiment of the present invention is described. 
         [0029]    The AMOLED display includes an input unit  51 , a controller  52 , and a display unit  53 . 
         [0030]    The input unit  51  inputs one of a low power mode and a high picture quality mode, and may be a touch pad or a keypad by which a user can select the mode, or a sensor that can automatically select the mode. 
         [0031]    The controller  52  receives a low power mode input signal or a high picture quality mode input signal from the input unit  51 , determines whether one of a low power mode and a high picture quality mode is input, outputs the low power mode control signal to the display unit  53  if the low power mode is input, and outputs a high picture quality mode control signal to the display unit  53  if the high picture quality mode is input. The controller of this exemplary embodiment may be formed as a microprocessor chip. 
         [0032]    The display unit  53  displays a low power mode screen or a high picture quality mode screen and includes an AMOLED  21  and a cholesteric Liquid Crystal Display (LCD)  28 . 
         [0033]    The cholesteric LCD  28  includes a first cholesteric liquid crystal color layer  22  stacked at an upper surface of the AMOLED  21 , a second cholesteric liquid crystal color layer  23  stacked at an upper part of the first cholesteric liquid crystal color layer  22 , and a third cholesteric liquid crystal color layer  24  stacked at an upper part of the second cholesteric liquid crystal color layer  23 . 
         [0034]    Referring to  FIG. 3 , in the present exemplary embodiment, the first cholesteric liquid crystal color layer  22  selectively reflects or transmits blue color light  38   c,  the second cholesteric liquid crystal color layer  23  selectively reflects or transmits green color light  38   b,  and the third cholesteric liquid crystal color layer  24  selectively reflects or transmits red color light  38   a.  However, the present invention is not limited thereto, and one of the three cholesteric liquid crystal color layers  22 ,  23 , and  24  can selectively reflect or transmit the red color light, another one can selectively reflect or transmit the green color light, and the remaining one can selectively reflect or transmit the blue color light. 
         [0035]    A first transparent electrode film  25  is attached to an upper surface of the first cholesteric liquid crystal color layer  22 , a second transparent electrode film  26  is attached to an upper surface of the second cholesteric liquid crystal color layer  23 , and a third transparent electrode film  27  is attached to an upper surface of the third cholesteric liquid crystal color layer  24 . The first transparent electrode film  25 , the second transparent electrode film  26 , and the third transparent electrode film  27  fix the first cholesteric liquid crystal color layer  22 , the second cholesteric liquid crystal color layer  23 , and the third cholesteric liquid crystal color layer  24 , respectively, and perform a function of applying a voltage in order to reflect or transmit desired light. Further, in this exemplary embodiment the transparent electrode films  25 ,  26 , and  27  are each made of Indium Tin Oxide (ITO), and a thickness thereof is preferably 0.05 μm to 0.12 μm. 
         [0036]    In a low power mode, the AMOLED  21  is turned off and performs a same function as that of the absorption layer  11  of  FIG. 1 . That is, because a black color cannot be expressed with only the cholesteric liquid crystal color layers  22 ,  23 , and  24 , an absorption layer for expressing a black color should exist, and when power is not supplied, a light emitting body does not operate and thus the AMOLED  21  theoretically completely becomes a black color and performs a function of an absorption layer that absorbs light  38   d.  Further, as the cholesteric LCD  28  is turned on, the first cholesteric liquid crystal color layer  22 , the second cholesteric liquid crystal color layer  23 , and the third cholesteric liquid crystal color layer  24  selectively reflect or transmit blue color light  38   c,  green color light  38   b,  and red color light  38   a , respectively. Accordingly, the AMOLED display can operate as a low power cholesteric LCD. 
         [0037]    Referring to  FIG. 4 , a high picture quality mode operation of the display unit  53  of  FIG. 2  is described. In a high picture quality mode, as the cholesteric LCD  28  is turned off, the first cholesteric liquid crystal color layer  22 , the second cholesteric liquid crystal color layer  23 , and the third cholesteric liquid crystal color layer  24  continue to transmit unfiltered all color light, i.e., all red color light  48   a , green color light  48   b,  and blue color light  48   c.  Further, as the AMOLED  21  is turned on, power is supplied and thus the AMOLED  21  is driven. Because the AMOLED  21  is formed by coating a kind of film (not shown) on a light emitting body, when external light is strong such a film can function as a reflector. Therefore, in order to prevent strong external light from being reflected, it is necessary to attach a circular polarization plate to an upper part thereof. In the AMOLED display according to the present exemplary embodiment, the cholesteric liquid crystal color layers  22 ,  23 , and  24  can perform a function of a circular polarization plate. More particularly, when a cholesteric liquid crystal cell has a thickness of 14 μm or more, right circular polarized light can be totally reflected and thus it is preferable that at least one of three cholesteric liquid crystal color layers  22 ,  23 , and  24  has each a thickness of 14 μm or more. 
         [0038]    According to the present exemplary embodiment, by stacking three cholesteric liquid crystal color layers  22 ,  23 , and  24  at an upper part of the AMOLED  21 , when used in an indoor environment or when viewing a motion picture, the AMOLED  21  can operate as a high picture quality AMOLED, and when used in an outdoor environment or as an e-book reader, the AMOLED  21  can operate as a cholesteric LCD of super low power. Further, because the AMOLED  21  of the present exemplary embodiment has a structure in which a circular polarization plate of an AMOLED display of the related art is replaced with a cholesteric LCD in which an absorption layer is removed instead of a simple combination of an AMOLED display of the related art and a conventional cholesteric LCD of the related art, a thickness and cost of the AMOLED  21  can be reduced further than those of a simple combination of a AMOLED of the related art display and a cholesteric LCD of the related art. 
         [0039]      FIG. 6  is a flowchart illustrating a method of controlling a display of the AMOLED display of  FIG. 5  according to an exemplary embodiment of the present invention. 
         [0040]    Referring to  FIGS. 2 to 6 , a method of displaying an AMOLED display according to an exemplary embodiment of the present invention is described. 
         [0041]    First, one of a low power mode and a high picture quality mode is input by the input unit  51  at step S 1 . 
         [0042]    The controller  52  determines whether a low power mode is input at step S 2 . 
         [0043]    If it is determined that the low power mode is input, the controller  52  controls the display unit  53  to display in the low power mode by turning off the AMOLED  21  and turning on the cholesteric LCD  28  at step S 3 . 
         [0044]    If it is determined that the low power mode is not input, i.e., if it is determined that the high picture quality mode is input at step S 2 , the controller  52  controls the display unit  53  to display in the high picture quality mode by turning on the AMOLED  21  and turning off the cholesteric LCD  28  at step S 4 . 
         [0045]    In this way, in a method of controlling a display of an AMOLED display according to the present exemplary embodiment, because a low power mode screen or a high picture quality mode screen can be displayed according to an input, an appropriate mode screen can be displayed according to a user environment or a user viewing image. 
         [0046]    As described above, according to an exemplary embodiment of the present invention, when used in an indoor environment or when viewing a motion picture, an AMOLED display may operate as an AMOLED of a high picture quality, and when used in outdoor environment or as an e-book reader, the AMOLED display can operate as a cholesteric LCD of super low power. 
         [0047]    While the invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents.