Abstract:
An electronic display includes a display unit for displaying both a two-dimensional image and a three-dimensional image, and a barrier facing the display unit to convert an image into the two-dimensional or three-dimensional image. The barrier includes first and second substrates facing each other, a plurality of first electrodes on the first substrate, an insulation layer on the first substrate and covering the first electrodes, a plurality of second electrodes on the insulation layer, and a liquid crystal layer disposed between the first and second substrates. The first electrodes are aligned with gaps between the second electrodes and the second electrodes are aligned with gaps between the first electrodes. Widths of the first electrodes may be equal to or greater than the gaps between the second electrodes. Widths of the second electrodes may be equal to or greater than the gaps between the first electrodes.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to and the benefit of Korean Patent Application No. 10-2007-0063740 filed in the Korean Intellectual Property Office on Jun. 27, 2007, the entire content of which is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to electronic displays, and, more particularly, to an autostereoscopic electronic display using a barrier. 
         [0004]    2. Description of the Related Art 
         [0005]    In electronic displays, a stereoscopic device can provide different images to left and right eyes of a user so that the user can preceive distance and have a stereoscopic sense of an image. An autostereoscopic electronic display is configured to provide a stereoscopic image to the user even when the user does not use an instrument such as polarizing spectacles. 
         [0006]    The conventional autostereoscopic electronic display employs a method for space-dividing an image displayed on an image display unit by providing, for example, a parallax barrier, a lenticular lens, or a micro-lens array on a front surface of the image display unit. 
         [0007]    The parallax barrier may be formed in a liquid crystal shutter using technologies such as a transmissive type of liquid crystal display. In this case, a mode conversion between a two-dimensional (2D) image mode and a three-dimensional (3D) mode (stereoscopic image mode) becomes possible. As such, the parallax barrier can be effectively applied to a laptop computer or a mobile phone. 
         [0008]    Generally, the parallax barrier includes light blocking portions arranged in a stripe pattern and light transmitting portions arranged in a stripe pattern. Therefore, a right eye image realized by right eye sub-pixels reaches the right eye of the user through the light transmitting portions of the parallax barrier and a left eye image realized by left eye sub-pixels reaches the left eye of the user through the light transmitting portions of the parallax barrier. Therefore, the user can perceive the image displayed on the image display unit as a stereoscopic image. 
         [0009]    However, since the electronic display having the parallax barrier is designed to divide the image into the right and left eye images to display the 3D image, the resolution of the 3D image is reduced to half the resolution of the 2D image. 
         [0010]    To solve this problem, a time-division driving type of electronic display has been developed. The time-division driving type of electronic display alternately displays the left and right eye images on the display unit at predetermined time intervals. In order to realize this, the parallax barrier forms light blocking portions and light transmitting portions such that patterns of the light blocking portions and light transmitting portions change with each other. By employing this time-division driving method instead of the space-division driving method, the electronic image display can display the 3D image with resolution that is not deteriorated. 
       SUMMARY OF THE INVENTION 
       [0011]    An exemplary embodiment of the present invention provides an electronic display that can display a stereoscopic image having high resolution using a parallax barrier. 
         [0012]    In an exemplary embodiment of the present invention, an electronic display includes a display unit for displaying a 2D image and/or a 3D image, and a barrier that is disposed facing the display unit to convert an image into the 2D or 3D image. The barrier includes first and second substrates facing each other. A plurality of first electrodes is formed on the first substrate. An insulation layer is formed on the first substrate and covers the first electrodes. A plurality of second electrodes is formed on the insulation layer. A liquid crystal layer is disposed between the first and second substrates. The first electrodes are aligned with gaps between the second electrodes and the second electrodes are aligned with gaps between the first electrodes. 
         [0013]    Widths of the first electrodes may be equal to or greater than the corresponding gaps between the second electrodes. 
         [0014]    Widths of the second electrodes may be equal to or greater than the corresponding gaps between the first electrodes. 
         [0015]    The first electrodes and the second electrodes may be arranged in stripe patterns, and the widths of the first electrodes may be substantially the same as those of the second electrodes. 
         [0016]    The gaps between the first electrodes may be substantially the same as those between the second electrodes. 
         [0017]    The widths of the first electrodes, the widths of the second electrodes, the gaps between the first electrodes, and the gaps between the second electrodes may be same as each other. 
         [0018]    When the widths of the first electrodes are substantially the same as those of the second electrodes and the gaps between the first electrodes are substantially the same as those between the second electrodes, the widths may be greater than the gaps. 
         [0019]    Both edges of each of the second electrodes in a width direction may overlap adjacent edges of the adjacent first electrodes. 
         [0020]    The electronic display may further include a third electrode formed on the second substrate. The third substrate may be formed in a single body on the whole surface of the second substrate. The barrier may be a normally white mode liquid crystal display. 
         [0021]    Further, the display unit may include first and second pixel groups that are alternately arranged in a direction in which the first electrodes are spaced apart from each other. A liquid crystal driving voltage may be applied to the first electrodes in a first period so that pixels of the first pixel groups display a left eye image and pixels of the second pixel groups display a right eye image. In addition, a liquid crystal driving voltage is applied to the second electrodes in a second period so that the pixels of the first pixel groups display the right eye image and the pixels of the second pixel groups display the left eye image. The left and right eye images are displayed through time-division driving. 
         [0022]    The barrier may be turned off when the display unit displays a 2D image. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  is a schematic sectional view of an electronic display according to a first exemplary embodiment of the present invention. 
           [0024]      FIG. 2A  is a partial top plan view illustrating first electrodes formed on a first substrate of a barrier of  FIG. 1 . 
           [0025]      FIG. 2B  is a partial top plan view illustrating second electrodes formed on a first substrate of a barrier of  FIG. 1 . 
           [0026]      FIG. 3  is a partial top plan view illustrating a relationship between first and second electrodes formed on a first substrate of a barrier of  FIG. 1 . 
           [0027]      FIG. 4A  is a view illustrating a pixel arrangement of a display unit of  FIG. 1  in a first period t 1 . 
           [0028]      FIG. 4B  is a view illustrating a pixel arrangement of a display unit of  FIG. 1  in a second period t 2 . 
           [0029]      FIG. 5  is a schematic sectional view of an electronic display according to another exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0030]    Referring to  FIG. 1 , an electronic display of an exemplary embodiment of the present invention includes a display unit  100  and a barrier  200 . 
         [0031]    The display unit  100  displays right and left eye images each having a predetermined pattern. In this case, the patterns of the left and right eye images can be realized by first and second images that are alternately displayed with a predetermined image frequency. 
         [0032]    Any display device may be used as the display unit  100 . For example, the display unit  100  may be one of a cathode ray tube (CRT), a liquid crystal display (LCD), a plasma display panel (PDP), a field emission display (FED), and an organic light emitting display (OLED). 
         [0033]    The barrier  200  may be formed of a normally white mode LCD that transmits light in an off-state and blocks the light in an on-state. 
         [0034]    In more detail, the barrier  200  includes first and second substrates  10 ,  12 , a plurality of first electrodes  14 , a plurality of second electrodes  16 , a third electrode  18 , and a liquid crystal layer  20 . 
         [0035]    The first and second substrates  10 ,  12  face each other with a predetermined interval therebetween. Each of the first and second substrates  10 ,  12  is formed of a rectangular glass plate having a pair of short-sides and a pair of long-sides. 
         [0036]      FIG. 2A  is a partial top plan view illustrating the first electrodes formed on the first substrate of the barrier of  FIG. 1 , and  FIG. 2B  is a partial top plan view illustrating the second electrodes formed on the first substrate of the barrier of  FIG. 1 . 
         [0037]    Referring to  FIG. 2A , the first electrodes  14  are formed on an inner surface of the first substrate  10 . The first electrodes  14  are spaced apart from each other. The first electrodes  14  are formed extending in a first direction (a Y-direction in  FIG. 2A ) that is in parallel with the short sides of the first substrate  10 . That is, the first electrodes  14  are arranged in a stripe pattern and spaced apart from each other by a predetermined gap G 1 . 
         [0038]    In addition, as shown in  FIG. 2A , a first connecting electrode  14   a  for electrically interconnecting the first electrodes  14  is formed on the first substrate  10 . The first connecting electrode  14   a  extends in a second direction (an X-direction in  FIG. 2A ), which is in parallel with the long-sides of the first substrate  10 , at first ends of the first electrodes  14 . 
         [0039]    Referring to  FIG. 2B , an insulation layer  22  is formed on the first substrate  10  while covering the first electrodes  14  and the first connecting electrode  14   a.  The insulation layer  22  may be formed of a transparent material such as SiO 2 . 
         [0040]    The second electrodes  16  are formed on the insulation layer  22  and arranged in a stripe pattern extending in the first direction (the Y-direction). That is, the second electrodes  16  are spaced apart from each other by a predetermined gap G 2 . Further, as shown in  FIG. 2B , a second connecting electrode  16   a  electrically interconnecting the second electrodes  16  is formed on the insulation layer  22 . The second connecting electrode  16   a  extends in the second direction (the X-direction in  FIG. 2B ) at first ends of the first electrodes  14 . The second electrodes  16  and the second connecting electrode  16   a  are insulated from the first electrodes  14  and the first connecting electrode  14   a  by the insulation layer  22 . 
         [0041]      FIG. 3  is a partial top plan view illustrating a relationship of the first and second electrodes formed on the barrier. 
         [0042]    Referring to  FIG. 3 , each of the first electrodes  14  has a predetermined width W 1  and each of the second electrodes  16  has a predetermined width W 2 . The first and second electrodes  14 ,  16  are alternately arranged in the second direction (the X-direction). The widths W 1 , W 2  may be substantially the same as each other. Further, in the present exemplary embodiment, the second electrodes  16  are disposed between the first electrodes  14  over the gap G 1  between the first electrodes  14 . The first electrodes  14  are disposed between the second electrodes  16  under the gap G 2  between the second electrodes  16 . 
         [0043]    That is, the widths W 1 , W 2  are substantially the same as each other and the gaps G 1 , G 2  are also substantially the same as each other. As shown in  FIG. 3 , the edges of the first electrodes  14  coincide with the edges of the second electrodes  15  on an X-Y plane. 
         [0044]    The third electrode  18  is formed on an inner surface of the second substrate  12 . The third electrode  18  may be provided as a single body or may be divided into a plurality of line sections extending in a direction intersecting the first and second electrodes  14 ,  16 . The first, second, and third electrodes  14 ,  16 ,  18  may be formed of a transparent material such as indium tin oxide (ITO). 
         [0045]    In addition, orientation layers (not shown) are formed above the second and third electrodes  16 ,  18 . The liquid crystal layer  20  is formed between the orientation layers. Further, polarizing plates  24  are respectively disposed on outer surfaces of the first and second substrates  10 ,  12 . 
         [0046]    The following will describe a pixel arrangement and operation of the display unit  100 .  FIGS. 4A and 4B  show pixel arrangements of the display unit for first and second periods t 1 , t 2 , respectively. The display unit  100  includes first pixel groups and second pixel groups that are alternately arranged in the first direction. Identical color pixels in the first and second pixel groups  26 ,  28  are arranged in the second (X) direction. 
         [0047]    As shown in  FIG. 4A , in the first period t 1 , pixels L R , L G , L B  of the first pixel groups  26  display a left eye image in response to a left eye video signal, and pixels R R , R G , R B  of the second pixel groups  28  display a right eye image in response to a right eye video signal. As described above, in the first period t 1 , a first image is displayed on the display unit. 
         [0048]    In the first period t 1  in which the display unit  100  displays the first image, a liquid crystal driving voltage is applied to the first electrodes  14  through the first connecting electrode  14   a  and a reference voltage (e.g., a ground voltage) is applied to the second electrodes  16  through the second connecting electrode  16   a.  In addition, a reference voltage is applied to the third electrode  18 . At this point, the first electrodes  14  function as light blocking portions and the second electrodes  16  function as light transmitting portions. 
         [0049]    As shown in  FIG. 4B , unlike the first period t 1 , in the second period t 2 , the pixels R R , R G , R B  of the first pixel groups  26  display a right eye image in response to the right eye video signal, and the pixels L R , L G , L B  of the second pixel groups  28  display a left eye image in response to a left eye video signal. As described above, in the second period t 2 , a second image is displayed on the display unit. 
         [0050]    In the second period t 2  in which the display unit  100  displays the second image, the liquid crystal driving voltage is applied to the second electrodes  16  through the second connecting electrode  16   a  and the reference voltage is applied to the first electrodes  14  through the first connecting electrode  14   a.  In addition, a reference voltage is applied to the third electrode  18 . At this point, the first electrodes  14  function as the light transmitting portions and the second electrodes  16  function as the light blocking portions. 
         [0051]    By driving the display unit  100  and the barrier  200  as described above, the left eye of the user receives the image realized by the pixels of the first pixel groups  26  during the first period t 1  and receives the image realized by the pixels of the second pixel groups  28  during the second period t 2 . In addition, the right eye of the user receives the image realized by the pixels of the second pixel groups  28  during the first period t 1  and receives the image realized by the pixels of the first pixel groups  26  during the second period t 2 . Therefore, since the stereoscopic image is realized through time-division rather than through space-division, the resolution of the stereoscopic image becomes substantially the same as that of the 2D image. 
         [0052]    In the present exemplary embodiment, no gap is formed between the adjacent first and second electrodes  14 ,  16  of the barrier  200 . Therefore, light leakage between the first and second electrodes  14 ,  16  is minimized. 
         [0053]    As a result, in the electronic display of the present exemplary embodiment, the deterioration of the 3D image, which is caused by crosstalk, can be prevented. 
         [0054]    Further, if required, the electronic display of the present exemplary embodiment can realize the 2D image mode by turning off the barrier and inputting a 2D video signal to the pixels of the first and second pixel groups of the display unit. 
         [0055]    The following will describe an electronic display according to another exemplary embodiment of the present invention. 
         [0056]      FIG. 5  is a sectional view of an electronic display according to another exemplary embodiment of the present invention. An electronic display of this exemplary embodiment is somewhat similar to that of the foregoing embodiment of  FIG. 1 . Therefore, in the following description, like parts of the exemplary embodiments will be assigned with like reference numerals and a description thereof will be omitted. 
         [0057]    As shown in  FIG. 5 , in barrier  210  first electrodes  15  are disposed on a first substrate  10  and arranged in a stripe pattern extending in a first (Y) direction. A gap G 3  between the adjacent first electrodes  15  is less than a width of each of the first electrodes  15 . In addition, second electrodes  17  are disposed on an insulation layer  22  and extend in the first direction. A gap G 4  between the adjacent second electrodes  17  is less than a width W 4  of each of the second electrodes  17 . The widths W 3 , W 4  may be substantially the same as each other. The gaps G 3 , G 4  may also be substantially the same as each other. 
         [0058]    Under this condition, when the first and second electrodes  15 ,  17  are alternately arranged in a second (X) direction, both edges of each of the second electrodes  17  overlap the first electrodes  15 . 
         [0059]    As such, the second electrodes  17  are disposed above the first electrodes  15  while overlapping the first electrodes  15  as well as the gaps G 3  between the first electrodes  15 . A width of each of the overlapping region between the first electrodes  15  and the second electrodes  17  is uniformly maintained. 
         [0060]    In the operation of the electronic display of this exemplary embodiment, the light transmitting portions of the barrier  210  are defined by the gaps G 3  between the first electrodes or the gaps G 4  of the second electrodes, and the light blocking portions are defined by the first electrodes  15  or the second electrodes  17 . 
         [0061]    Since a width of the light transmitting portion is less than that of the light blocking portion due to the arrangement of the first and second electrodes  15 ,  17 , light leakage between the first and second electrodes  15 ,  17  during the operation of the barrier  210  can be prevented. 
         [0062]    While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.