Abstract:
Provided is a display device. The display device includes a display portion configured to display an image, a photo sensor electrically connected to the display portion and configured to facilitate correction of an afterimage of the display portion; and a shutter portion disposed on the display portion and comprising a shutter positioned and configured to selectively block light over an afterimage correction pattern generated by the correction of the afterimage facilitated by the photo sensor, so as to selectively prevent a user from viewing a portion of the display portion upon which the afterimage correction pattern occurs.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This U.S. non-provisional patent application claims priority under 35 U.S.C. §119 to Korean Patent Application No. 10-2014-0173908 filed on Dec. 5, 2014, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND 
     The present disclosure relates generally to flat panel display devices, and more particularly to flat panel display devices capable of correcting afterimages. 
     A display device performs an afterimage correction process using a photo sensor after being powered off. During such afterimage correction, a user may perceive an undesirable afterimage correction pattern. 
     SUMMARY 
     The present disclosure provides a display device capable of reducing or eliminating the perception of afterimage correction patterns. 
     Issues to be addressed in the present disclosure are not limited to those described above and other issues unmentioned above will be clearly understood by those skilled in the art from the following description. 
     Embodiments of the inventive concept provide display devices including: a display portion configured to display an image; a photo sensor electrically connected to the display portion and configured to facilitate correction of an afterimage of the display portion; and a shutter portion disposed on the display portion and including a shutter positioned and configured to selectively block light over an afterimage correction pattern generated by the correction of the afterimage facilitated by the photo sensor, so as to selectively prevent a user from viewing a portion of the display portion upon which the afterimage correction pattern occurs. 
     In some embodiments, the display portion may include an organic light emitting display (OLED). 
     In other embodiments, the shutter may include an electro wetting display (EWD). 
     In still other embodiments, the shutter may include a liquid crystal display. 
     In even other embodiments, the shutter may substantially entirely cover the display portion. 
     In yet other embodiments, the shutter may cover only those parts of the display portion on which the photo sensor is disposed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the inventive concept, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the inventive concept and, together with the description, serve to explain principles of the inventive concept. In the drawings: 
         FIG. 1A  is a plan view of a front surface of a display device according to an embodiment of the inventive concept; 
         FIG. 1B  is a plan view of a rear surface of the display device of  FIG. 1A ; 
         FIG. 2  is a plan view illustrating a display device according to another embodiment of the inventive concept; 
         FIG. 3A  and  FIG. 33  are cross-sectional views illustrating further details of a shutter portion of a display device according to an embodiment of the inventive concept; and 
         FIG. 4A  and  FIG. 4B  are cross-sectional views illustrating further details of a shutter portion of a display device according to another embodiment of the inventive concept. 
     
    
    
     The various Figures are not to scale. 
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Objects, other objects, features and advantages of the present disclosure will become more easily understood to those of ordinary skill in the art with the following detailed description and accompanying drawings. The inventive concepts may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. The different features of the various embodiments, disclosed or otherwise understood, can be mixed and matched in any manner to produce further embodiments within the scope of the invention. 
     It will be understood that when an element is referred to as being “on” another element, it can be directly on the other element or intervening elements may also be present. In addition, in the drawings, the thicknesses of elements are exaggerated for effective explanation. 
     Example embodiments are described herein with reference to cross-sectional views and/or plan views that are schematic illustrations of example embodiments. In the drawings, the thicknesses of layers and regions are exaggerated for clarity. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, example embodiments should not be construed as limited to the particular shapes of regions illustrated herein but may be to include deviations in shapes that result, for example, from manufacturing. For example, an implanted region illustrated as a rectangle may, typically, have rounded or curved features. Thus, the regions illustrated in the figures are schematic in nature and their shapes may be not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of example embodiments. It will be understood that although the terms “first”, “second”, etc. may be used herein to describe various components, these components should not be limited by these terms. These terms are only used to distinguish one element from another element. An embodiment described and exemplified herein includes a complementary embodiment thereof. 
     The terms and words used in the following description and claims are to describe embodiments but are not limited the inventive concept. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising” used herein specify the presence of stated features or components, but do not preclude the presence or addition of one or more other features or components. 
     Hereinafter, specific embodiments will be described in detail with reference to the accompanying drawings. 
       FIG. 1A  is a plan view illustrating front surface of a display device according to an embodiment of the inventive concept, and  FIG. 1B  is a plan view illustrating rear surface of the display device of  FIG. 1A .  FIG. 2  is a plan view illustrating a display device according to another embodiment of the inventive concept.  FIG. 3A  and  FIG. 3B  are cross-sectional views illustrating details of a shutter portion of a display device according to an embodiment of the inventive concept. 
     Referring to  FIG. 1A ,  FIG. 1B ,  FIG. 2 ,  FIG. 3A  and  FIG. 3B , a display device includes a display portion  100 , photo sensors  300 , and a shutter portion  200 . 
     The display portion  100  includes a substrate  110 , first and second electrodes  120  and  140  disposed facing and separate from each other on the substrate  110 , and an organic light emitting layer  130  disposed between the first and second electrodes  120  and  140 . In the present embodiment, the display portion  100  is exemplarily described as, but is not limited to, an organic light emitting diode (OLED). 
     The substrate  110  may include, but is not limited to, glass, a transparent plastic, or quartz. 
     The first electrode  120  is disposed on a first surface of the substrate  110  and may be a pixel electrode or a positive electrode. As an example, the first electrode  120  may be a transmissive electrode. The first electrode  120  may be formed of a transparent metal oxide, for example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium tin zinc oxide (ITZO), etc. As another example, the first electrode  120  may be a semi-transmissive electrode or a reflective electrode. 
     The second electrode  140  is separated from the first electrode  120  and may be a common electrode or a negative electrode. As an example, the second electrode  140  may include Li, Ca, LiF/Ca, LiF/Al, Al, Mg, Ag, or a compound or a mixture (e.g., a mixture of Ag and Mg) thereof. As another example, the second electrode  140  may include a transparent conductive film formed of ITO, IZO, ZnO, ITZO, etc. 
     Electrons and holes from the first and second electrodes  120  and  140  are combined to generate excitons in the organic light emitting layer  130  and the excitons emit light through stabilization (losing energy). Hole transport materials may be further included between the first electrode  120  and the organic light emitting layer  130  and electron transport materials may be further included between the second electrode  140  and the organic light emitting layer  130 . 
     When the display device is powered off, the photo sensors  300  perform a function of COM an afterimage on the display portion  100 . In  FIG. 1B , 6 photo sensors that are spaced apart from each other along opposing edges of the display device. However, the number and disposition of the photo sensors  300  are not limited hereto. Any number of photo sensors  300  is contemplated, where these photo sensors  300  can be positioned at any locations on the display portion  100 . 
     In the present embodiment, the photo sensors  300  are electrically connected to the display portion  100 . As an example, the photo sensors  300  may be disposed on the bottom surface of the display portion  100 , namely, on the second electrode  140 . While the photo sensors  300  correct the afterimage of the display portion  100 , as illustrated in  FIGS. 1A and 1B , afterimage correction patterns PT are formed on the top surface of the display device. These afterimage correction patterns PT would ordinarily be perceptible by a user. Accordingly, to prevent the user from seeing these afterimage correction patterns PT, in embodiments of the inventive concept, the shutter portion  200  is disposed on the display portion  100 . 
     The shutter portion  200  may cover the afterimage correction patterns PT on the display portion  100 . According to an embodiment of the inventive concept, the shutter portion  200  includes an electro wetting display (EWD), although any display type is contemplated. 
     The EWD  200  according to an embodiment of  FIG. 1  entirely covers the display portion  100  and is disposed on the display portion  100  (i.e. positioned between the display portion  100  and a user/viewer of the display device). Alternatively, an EWD  200  according to another embodiment of  FIG. 2  may be disposed to selectively cover the afterimage correction patterns on the display portion  100 . 
     In  FIGS. 3A and 3B , the EWD  200  may include an EWD electrode  210  disposed on the substrate  110  of the display portion  100 , a hydrophobic organic film  220  disposed on the EWD electrode  210 , partitions  230  disposed on the hydrophobic organic film  220 , black oil  240  in a space formed by the partitions  230 , and water  250  filling the inside of the EWD  200  on the black oil  240 . The space outlined by the partitions  230  may correspond to pixel areas of the display portion  100 . 
     The EWD  200  uses the principle that the water  250  does not mix with the black oil  240 . As illustrated in  FIG. 3A , when a voltage is not applied to the EWD electrode  210 , the black oil  240  covers substantially the entire hydrophobic organic film  220  so that all a user perceives is a black color. On the contrary, as illustrated in  FIG. 3B , when a voltage is applied to the EWD electrode  210 , the black oil  240  accumulates over only a part of the hydrophobic organic film  220  leaving the rest of organic film  220  to pass light, i.e. an image, from display portion  100 . 
     During the time when the display device is powered off and the photo sensors  300  operate to correct for afterimages, when a voltage is not applied to the EWD electrode  210  of the shutter portion  200 , the shutter portion  200  may be in a black state, i.e. may block light so that users sec only black. Accordingly, the user may not perceive the afterimage correction patterns PT. 
       FIGS. 4A and 4B  are cross-sectional views for explaining a shutter portion of a display device according to another embodiment of the inventive concept.  FIGS. 4A and 4B  are cross-sectional views of an alternate construction of the display panel of  FIGS. 1A and 1B . 
     Referring to  FIGS. 4A and 4B , the display device includes a display portion  100 , photo sensors  300 , and a shutter portion  400 . 
     The display portion  100  includes a substrate  110 , first and second electrodes  120  and  140  disposed facing and separate from each other on the substrate  110 , and an organic light emitting layer  130  disposed between the first and second electrodes  120  and  140 . 
     The shutter portion  400  is disposed on the substrate  110  of the display portion  100 , In the present embodiment, the shutter portion  400  includes a liquid crystal display (LCD) although, as above, any other display type is contemplated. 
     Although  FIGS. 4A and 4B  show LCD  400  entirely or substantially entirely covering the display portion  100 , the LCD  400  may be disposed to cover less than the entirety of display portion  100 , such as only a portion in which afterimage correction patterns PT appear on the substrate  110  of the display portion  100 . 
     The LCD  400  includes first and second LCD electrodes  410  and  420  disposed facing and separate from each other on the substrate  110  of the display portion  100 , and a liquid crystal layer  430  filling the gap between the first and second LCD electrodes  410  and  420 . An electric field is formed inside the liquid crystal layer  430  by a difference in voltages applied to the first and second LCD electrodes  410  and  420 , and an alignment direction of the liquid crystal molecules  440  inside the liquid crystal layer  430  is thereby changed. The alignment direction of the liquid crystal molecules  440  imparted by this electric field selectively transmits or blocks light as desired. Similar to the embodiment of  FIGS. 3A and 3B , on shutdown, the LCD  400  selectively displays a black image over any areas where the undesired visual effects of afterimage correction occur (or over any other areas that may have an undesired visual effect), thus preventing the user from seeing any such undesirable visual effects. 
     Elements of the display portion  100  and the photo sensors  300  not described in relation to  FIGS. 4A and 4B  are substantially the same as elements described in relation to  FIGS. 1A, 1B, 2, 3A and 3B , and descriptions thereof will be omitted. 
     According to embodiments of the inventive concept, during correcting of afterimages using photo sensors, undesirable visual effects may be produced. These undesired effects of afterimage correction may be selectively obscured by an additional display panel that acts as a shutter, displaying a black patch over only those areas in which these undesirable visual effects occur. 
     The above-disclosed subject matter is to be considered illustrative and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments, which fall within the true spirit and scope of the inventive concept. Thus, to the maximum extent allowed by law, the scope of the inventive concept is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description.