Abstract:
A three-dimensional display device according to the present invention includes a panel that time-shares images and displays left and right eye images, a panel control unit for controlling the panel by applying a display control signal that includes vertical and horizontal signals to the panel, a barrier facing the panel and separating the images of the panel into user left and right eye images, and a barrier control unit for controlling the barrier. The panel can be converted between a first mode of a portrait-type view and a second mode of a landscape-type view, and the barrier may be operated corresponding to the mode conversion of the panel.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to and the benefit of Korean Patent Application No. 10-2005-0105342, filed in the Korean Intellectual Property Office, on Nov. 4, 2005, the entire content of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a three-dimensional display device, and in particular, to an autostereoscopic three-dimensional display device using a parallax barrier, and a driving method thereof. 
     2. Description of the Related Art 
     A three-dimensional display device may be categorized as a stereoscopic display device where a user wears viewing aids, such as polarizing glasses, or an autostereoscopic display device where the user can see a desired three-dimensional image without wearing such viewing aids. 
     A common autostereoscopic display device utilizes an optical separation element, such as a lenticular lens, a parallax barrier, or a microlens array, to spatially separate or isolate the left-eye image part and the right-eye image part displayed at an image display unit in the directions of the left and right eyes of the user, respectively. 
     In particular, the parallax barrier may be formed with a liquid crystal shutter utilizing a transmission type of liquid crystal display, and in this case, it may be converted between a two-dimensional mode and a three-dimensional mode. Thus the parallax barrier can be applied to laptop computers or cellular phones. 
     The parallax barrier includes stripe-shaped light interception portions and light transmission portions. The parallax barrier selectively separates left and right eye images displayed at the image display unit through the light transmission portions such that the left and right eye images are respectively provided to the left and right eyes of the user. 
     Generally, a three-dimensional display device of the parallax barrier type spatially separates the left and right eye images. 
     However, the resolution of a three-dimensional image produced by such a display device is no more than half as fine as that of two-dimensional images produced by such a display device because the right and left eye images of the latter are provided to the respective eyes of the user. 
     Recently, display devices that can provide both portrait-type views and landscape-type views by rotating the display device have been developed. 
     However, conventional parallax barriers are adapted to provide only one of the portrait- or landscape-type views. 
     SUMMARY OF THE INVENTION 
     It is an aspect of the present invention to provide a three-dimensional display device and a driving method of the three-dimensional display device that can display a three-dimensional image having a high resolution when the three-dimensional display device is oriented to provide a portrait-type view and when it is oriented to provide a landscape-type view. 
     A three-dimensional display device according to the present invention includes a panel adapted to time-share a image and to display left and right eye images, a panel control unit for controlling the panel by applying a display control signal that includes vertical and horizontal signals to the panel, a barrier facing the panel and for separating the image of the panel into left and right eye images, and a barrier control unit for controlling the barrier. The panel may be adapted to be oriented in a first mode providing a portrait-type view and a second mode providing a landscape-type view, and the barrier may be operated corresponding to the orientation mode of the panel. 
     The barrier may include a first substrate, a plurality of first electrodes arranged along a first direction on the first substrate, a plurality of second electrodes arranged between the first electrodes on the first substrate, a second substrate facing the first substrate, a plurality of third electrodes arranged on the second substrate along a second direction that is perpendicular to the first direction, a plurality of fourth electrodes arranged between the third electrodes on the second substrate, and a liquid crystal layer located between the first substrate and the second substrate. 
     The barrier control unit may be adapted to apply a reference voltage or a driving voltage to the first, second, third, and fourth electrodes according to a barrier control signal synchronized with the vertical signal. 
     The vertical signal may have a higher level voltage during a first period, a lower level voltage during a second period following the first period, the higher level voltage during a third period following the second period, the higher level voltage during a fourth period following the third period. The first, second, third, and fourth periods constitute a repeatable cycle. 
     The panel may display, during the first period, a first image including the left and right eye images formed in a first pattern, and the panel may display, during the third period, a second image including the left and right eye images formed in a second pattern. The second pattern is opposite to the first pattern. 
     When the panel is oriented in the first mode, a plurality of first pixel columns and a plurality of second pixel columns respectively corresponding to the third electrodes and the fourth electrodes may be arranged along the second direction and arranged alternately and repeatedly along the first direction on the panel. 
     The left eye image and the right eye image of the first image may be displayed on the first pixel columns and the second pixel columns, respectively, during the first period. 
     The right eye image and the left eye image of the second image may be displayed on the first pixel columns and the second pixel columns, respectively, during the third period. 
     When the panel is oriented in the second mode, a plurality of first pixel rows and a plurality of second pixel rows respectively corresponding to the first electrodes and the second electrodes may be arranged along the second direction and arranged alternately and repeatedly along the first direction on the panel. 
     The left eye image and the right eye image of the first image may be displayed on the first pixel rows and the second pixel rows, respectively, during the first period. 
     The right eye image and the left eye image of the second image may be displayed on the first pixel rows and the second pixel rows, respectively, during the third period. 
     When the panel is oriented in the first mode, the reference voltage may be applied to the first electrodes and the second electrodes during the first period, the second period, the third period, and the fourth period. 
     The driving voltage may be applied to the third electrodes during the first period and to the fourth electrodes during the third period. 
     When the panel is oriented in the second mode, the reference voltage may be applied to the third electrodes and the fourth electrodes during the first period, the second period, the third period, and the fourth period. 
     The driving voltage may be applied to the first electrodes during the first period and to the second electrodes during the third period. 
     The barrier may further include a first connection electrode for electrically connecting the first electrodes to each other, a second connection electrode for electrically connecting the second electrodes to each other, a third connection electrode for electrically connecting the third electrodes to each other, and a fourth connection electrode for electrically connecting the fourth electrodes to each other. 
     The panel may separate the image into the left and right eye images by subpixel units. 
     The panel may separate the image into the left and right eye images by pixel units. 
     A driving method of the three-dimensional display device according to the present invention includes applying the display control signal to the panel and the barrier control unit, applying the barrier driving signal to the barrier, applying a reference voltage or a driving voltage to electrodes of the barrier according to the barrier driving signal, forming light transmission portions and light interception portions in the barrier according to operation of the liquid crystal layer according to application of the driving voltage, and indicating the display control signal on the panel. By way of example, the display control signal may include an image signal (e.g., R, G, and B data), a horizontal signal, and a vertical signal. 
     The reference voltage may be a ground voltage, and the driving voltage may be a predetermined positive or negative voltage. 
     The driving voltage may alternate between a positive level and a negative level at a predetermined frequency. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic block diagram of a three-dimensional display device according to an exemplary embodiment of the present invention. 
         FIG. 2  is a partial sectional view of a barrier of the three-dimensional display device according to the exemplary embodiment of the present invention. 
         FIG. 3  is a plan view of first electrodes and second electrodes formed on a first substrate. 
         FIG. 4  is a plan view of third electrodes and fourth electrodes formed on a second substrate. 
         FIG. 5  is a perspective view of an electronic device operating in a first mode for which the three-dimensional display device according to the exemplary embodiment of the present invention has been adapted. 
         FIG. 6  is a graph showing relationships between a vertical signal and voltages applied to the third electrodes and the fourth electrodes when the three-dimensional display device is oriented in the first mode. 
         FIG. 7A  is a schematic view showing arrays of pixels in the first mode during the first period. 
         FIG. 7B  is a schematic view showing arrays of pixels in the first mode during the third period. 
         FIG. 8A  is a schematic view showing an operation of the first electrodes and the second electrodes in the first mode. 
         FIG. 8B  is a schematic view showing an operation of the third electrodes and the fourth electrodes in the first mode. 
         FIG. 9  is a perspective view of an electronic device operating in a second mode for which the three-dimensional display device according to the exemplary embodiment of the present invention has been adapted. 
         FIG. 10  is a graph showing relationships between the vertical signal and voltages applied to the first electrodes and the second electrodes when the three-dimensional display device is oriented in the second mode. 
         FIG. 11A  is a schematic view showing arrays of the pixels in the second mode during the first period. 
         FIG. 11B  is a schematic view showing arrays of the pixels in the second mode during the third period. 
         FIG. 12A  is a schematic view showing an operation of the first electrodes and the second electrodes in the second mode. 
         FIG. 12B  is a schematic view showing the operation of the third electrodes and the fourth electrodes in the second mode. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which certain exemplary embodiments of the present invention are shown. 
       FIG. 1  is a schematic block diagram of a three-dimensional display device according to an exemplary embodiment of the present invention. As shown in  FIG. 1 , the three-dimensional display device includes a panel  100 , a panel control unit  110 , a barrier  200 , and a barrier control unit  210 . 
     A display control signal D including an image signal (e.g. R, G, and B data), a horizontal signal, and a vertical signal is input to each of the barrier control unit  210  and the panel  100  by the panel control unit  110 . 
     The panel  100  displays left and right eye images having a certain or predetermined pattern according to the display control signal D input by the panel control unit  110 . 
     In the exemplary embodiment of the present invention, a first image and a second image that have different patterns of the left and right eye images relative to each other are repeatedly displayed at a frequency, which may be predetermined. 
     Any suitable display device may be used as the panel  100 . For instance, the panel  100  may be formed with a cathode ray tube, a liquid crystal display, a plasma display panel, a field emission display device, an organic electroluminescence display device, or any other suitable display device(s). 
     The barrier control unit  210  receives the display control signal D from the panel control unit  110  and it operates the barrier  200 . 
     Electrodes of the barrier  200  are formed (or arranged) in a fashion that can separate the right and left eye images during operation in a first mode M 1  to provide a portrait-type view and during operation in a second mode M 2  to provide a landscape-type view. 
     The arrangement of the electrodes will be described more fully hereinafter with respect to the drawings. 
       FIG. 2  shows a partial sectional view of the barrier  200  of the three-dimensional display device according to the exemplary embodiment of the present invention. As shown in  FIG. 2 , the barrier  200  includes a first substrate  10  and a second substrate  12  having a certain or predetermined distance therebetween. The first substrate  10  and the second substrate  12  may be formed as rectangular glass substrates. 
     Electrodes for operating liquid crystals  22  located between the first substrate  10  and the second substrate  12  are formed on respective inner surfaces of the first substrate  10  and the second substrate  12 . 
     First electrodes  14  and second electrodes  16  (shown in  FIG. 3 , for example) are formed on the first substrate  10 , and third electrodes  18  and fourth electrodes  20  are formed on the second substrate  12 . 
     The first electrodes  14 , second electrodes  16 , third electrodes  18 , and fourth electrodes  20  may be formed with a transparent material such as indium tin oxide (ITO). The structure of these electrodes will be described more fully hereinafter. 
       FIG. 3  is a plan view of the first electrodes and the second electrodes formed on the first substrate. As shown in  FIG. 3 , the first electrodes  14  are formed to extend along a first direction corresponding to a shorter side of the first substrate  10  (the direction of the X-axis of  FIG. 3 ) on the first substrate  10 . 
     The first electrodes  14  are formed at intervals (e.g., predetermined intervals) on the first substrate  10  in a striped pattern. 
     In addition, a first connection electrode  14   a  that electrically connects the first electrodes  14  is formed on the first substrate  10  to extend along a second direction (the direction of the Y-axis of  FIG. 3 ) that is perpendicular to the first direction, and the first connection electrode  14   a  is connected to an end of each of the first electrodes  14 . 
     In substantially the same way as the first electrodes  14  and the first connection electrode  14   a  are arranged, the second electrodes  16  and a second connection electrode  16   a  that electrically connects the second electrodes  16  are formed on the first substrate  10 . In particular, the second electrodes  16  are formed on the first substrate  10  to extend along the first direction, and are arranged between the first electrodes  14  in a striped pattern. 
     In addition, the second connection electrode  16   a  is formed on the first substrate  10  to extend along the second direction that is perpendicular to the first direction and is connected to an end of each of the second electrodes  16 . 
     The first electrodes  14  and the second electrodes  16  and the first connection electrode  14   a  and the second connection electrode  16   a  formed on the first substrate  10  cover substantially all the inner surface area of the first substrate  10  corresponding to an active display area of the panel  100 , the coverage not including gaps formed between the first electrodes  14  and the second electrodes  16 . 
       FIG. 4  is a plan view of the third electrodes and the fourth electrodes formed on the second substrate  12 . As shown in  FIG. 4 , the third electrodes  18  and the fourth electrodes  20 , and a third connection electrode  18   a  that connects the third electrodes  18  and a fourth connection electrode  20   a  that connects the fourth electrodes  20  are formed on the second substrate  12 . 
     The third electrodes  18  and the fourth electrodes  20  are arranged to extend along the second direction (the direction of the Y-axis in  FIG. 4 ) that is perpendicular to the first direction (the direction of the X-axis in  FIG. 4 ) and are arranged in a striped pattern. 
     More specifically, the first electrodes  14  and the second electrodes  16  and the third electrodes  18  and the fourth electrodes  20  are arranged to be perpendicular to each other when the first substrate  10  and the second substrate  12  are arranged opposite one another. 
     The third electrodes  18  and the fourth electrodes  20  and the third connection electrode  18   a  and the fourth connection electrode  20   a  formed on the second substrate  12  cover substantially all the inner surface area of the second substrate  12  corresponding to the active display area of the panel  100 , the coverage not including gaps formed between the third electrodes  18  and the fourth electrodes  20 . 
     A driving method in which the three-dimensional display device according to the exemplary embodiment of the present invention is operated will be described hereinafter in more detail. 
       FIG. 5  shows an electronic device for which the three-dimensional display device according to the exemplary embodiment of the present invention is used. As shown, the electronic device may be a mobile phone. 
     During operation of the three-dimensional display device in the first mode M 1 , the panel  100  displays a portrait-type view. Generally, operation of the barrier corresponds to an orientation of the panel. The driving method of the three-dimensional display device will be described more concretely hereinafter. 
       FIG. 6  shows in graphical form relationships between the vertical signal, a voltage applied to the third electrodes  18 , and a voltage applied to the fourth electrodes  20  in the first mode M 1 . 
     The vertical signal input by the panel control unit  110  includes a series of voltages. During a first period T 1 , the vertical signal has a higher level voltage. During a second period T 2 , the vertical signal has a lower level voltage. During a third period T 3 , the vertical signal has the higher voltage. During a fourth period T 4 , the vertical signal has the lower level voltage. 
     The barrier  200  is operated by a barrier driving signal that is synchronized with the vertical signal. That is, during the first period T 1 , a driving voltage is applied to the third electrodes, and during the third period T 3 , the driving voltage is applied to the fourth electrodes. 
     An operation of the panel in the first mode M 1  will be described hereinafter in more detail.  FIGS. 7A and 7B  each show an array of pixels. First pixel columns  30  and second pixel columns  32  are formed along the second direction (the direction of the Y-axis in  FIG. 7A ) and are arranged alternately and repeatedly along the first direction (the direction of the X-axis in  FIG. 7A ). 
     As shown in  FIG. 7A , in the first period T 1 , the first pixel columns  30  display the left eye image corresponding to a left eye image signal, and the second pixel columns  32  display a right eye image corresponding to a right eye image signal. In more detail, sub pixels of the first pixel columns  30  display R R , R G  and R B  images. Similarly, sub pixels of the second pixel columns  32  display L R , L G  and L B  images. 
     Accordingly, a first image is displayed on the panel during the first period T 1 . 
     Then, as shown in  FIG. 7B , in the third period T 3 , the first pixel columns  30  display a right eye image corresponding to a right eye image signal, and the second pixel columns  32  display a left eye image corresponding to a left eye image signal. Accordingly, a second image is displayed on the panel during the third period T 3 . 
     An operation of the electrodes in the first mode M 1  will be described hereinafter.  FIG. 8A  shows an operation of the first electrodes and the second electrodes during the first period T 1 . 
     As shown in  FIG. 8A , a reference voltage such as a ground voltage is applied to each of the first electrodes  14  and the second electrodes  16  through the first connection electrode  14   a  and the second connection electrode  16   a , respectively. Accordingly, the first electrodes  14  and the second electrodes  16  are operated like a single-body electrode. 
       FIG. 8B  shows an operation of the third electrodes and the fourth electrodes during the period T 1 . As shown in  FIG. 8B , in the first period T 1  in which the panel displays the first image, the driving voltage is applied to the third electrodes  18  through the third connection electrode  18   a , and a reference voltage such as a ground voltage is applied to the fourth electrodes  20  through the fourth connection electrode  20   a.    
     Although  FIG. 8B , by way of example, shows that the driving voltage is a positive voltage, the driving voltage may also be a negative voltage or a voltage such that a positive voltage and a negative voltage are alternated according to a certain frequency. 
     Accordingly, during the first period T 1  in the first mode M 1 , the first electrodes  14  and the second electrodes  16  that cover substantially all the inner surface area of the first substrate  10  serve as a common electrode, and the third electrodes  18  formed on the second substrate  12  operate the liquid crystals  22  (see  FIG. 2 , for example). 
     When the barrier  200  is a liquid crystal display using a normally black mode of transmission, portions of the barrier on which the third electrodes  18  are located serve as light transmission portions, and portions of the barrier on which the fourth electrodes  20  are located serve as light interception portions during the first period T 1 . 
     When the barrier  200  is a liquid crystal display using a normally white mode of transmission, portions of the barrier on which the third electrodes  18  are located serve as light interception portions, and portions of the barrier on which the fourth electrodes  20  are located serve as light transmission portions during the first period T 1 . 
     Accordingly, the barrier  200  features a striped pattern such that the light transmission portions of the barrier are formed to extend along the second direction (the direction of the Y-axis in  FIGS. 8A and 8B ). 
     In the third period T 3  during which the panel displays the second image, the reference voltage is applied to the third electrodes  18  through the third connection electrode  18   a , and the driving voltage is applied to the fourth electrodes  20  through the fourth connection electrode  20   a.    
     Accordingly, during the third period T 3  in the first mode M 1 , the first electrodes  14  and the second electrodes  16  serve as a common electrode, and the fourth electrodes  20  operate the liquid crystals  22  (see  FIG. 2 , for example). 
     When the barrier  200  is a liquid crystal display using a normally black mode of transmission, portions of the barrier on which the fourth electrodes  20  are located serve as light transmission portions, and portions of the barrier on which the third electrodes  18  are located serve as light interception portions during the third period T 3 . 
     When the barrier  200  is a liquid crystal display using a normally white mode of transmission, portions of the barrier on which the fourth electrodes  20  are located serve as light interception portions, and portions of the barrier on which the third electrodes  18  are located serve as light transmission portions during the third period T 3 . 
     Accordingly, in the third period T 3 , a pattern of the light transmission portions and the light interception portions is formed that is opposite to the pattern of the light transmission portions and the light interception portions formed in the first period T 1 . 
     In this way, the array of the pixels formed on the panel and the pattern formed of the electrodes on the barrier correspond to each other in the first period T 1  and in the third period T 3 . 
     According to the operation of the panel and the barrier, the left eye of a user sees the image displayed by the first pixel columns  30  during the first period T 1 , and sees the image displayed by the second pixel columns  32  during the third period T 3 . 
     Furthermore, the right eye of the user sees the image displayed by the second pixel columns  32  during the first period T 1 , and sees the image displayed by the first pixel columns  30  during the third period T 3 . Accordingly, the user can see a three-dimensional image having a resolution that is equal to a resolution of a 2D image. 
     An operation of the three-dimensional display device according to the exemplary embodiment of the present invention in the second mode M 2  will be described hereinafter in more detail. 
     FIG.  FIG. 9  shows an electronic device for which the three-dimensional display device according to the exemplary embodiment of the present invention is used. As shown, the electronic device may be a mobile phone. 
     During operation of the three-dimensional display device in the second mode M 2 , the panel  100  displays a landscape-type view. Generally, operation of the barrier corresponds to an orientation of the panel. The driving method of the three-dimensional display device will be described more concretely hereinafter. 
       FIG. 10  shows in graphical form relationships between the vertical signal, a voltage applied to the first electrodes  14 , and a voltage applied to the second electrodes  16  in the second mode M 2 . 
     The vertical signal input by the panel control unit  110  includes a series of voltages. During a first period T 1 , the vertical signal has a higher level voltage. During a second period T 2 , the vertical signal has a lower level voltage. During a third period T 3 , the vertical signal has the higher level voltage. During a fourth period T 4 , the vertical signal has the lower level voltage. 
     The barrier  200  is operated by the barrier driving signal that is synchronized with the vertical signal. Accordingly, the driving voltage is applied to the first electrodes during the first period T 1 , and the driving voltage is applied to the second electrodes during the third period T 3 . 
       FIGS. 11A and 11B  each show an array of pixels. First pixel rows  34  and second pixel rows  36  are formed along the second direction (the direction of the Y-axis in  FIG. 11A ) and are arranged alternately and repeatedly along the first direction (the direction of the X-axis in  FIG. 11A ). 
     As shown in  FIG. 11A , in the first period T 1 , the first pixel rows  34  display the left eye image corresponding to the left eye image signal, and the second pixel rows  36  display the right eye image corresponding to the right eye image signal. 
     Accordingly, a first image is displayed on the panel during the first period T 1 . 
     Then, as shown in  FIG. 11B , in the third period T 3 , the first pixel rows  34  display the right eye image corresponding to the right eye image signal, and the second pixel rows  36  display the left eye image corresponding to the left eye image signal. 
     Accordingly, a second image is displayed on the panel during the third period T 3 . 
     An operation of the electrodes in the second mode M 2  will be described hereinafter in more detail.  FIG. 12A  shows an operation of the first electrodes and the second electrodes during the first period T 1 . 
     As shown in  FIG. 12A , in the first period T 1 , in which the panel displays the first image, the driving voltage is applied to the first electrodes  14  through the first connection electrode  14   a , and a reference voltage such as a ground voltage is applied to the second electrodes  16  through the second connection electrode  16   a.    
     Although  FIG. 12A , by way of example, shows that the driving voltage is a positive voltage, the driving voltage may also be a negative voltage or a voltage such that a positive voltage and a negative voltage are alternated according to a certain frequency. 
     As shown in  FIG. 12B , a reference voltage such as a ground voltage is applied to each of the third electrodes  18  and the fourth electrodes  20  through the third connection electrode  18   a  and the fourth connection electrode  18   a , respectively. Accordingly, the third electrodes  18  and the fourth electrodes  20  are operated like a single-body electrode. 
     Accordingly, during the first period T 1  in the second mode M 2 , the first electrodes  14  and the second electrodes  16  operate the liquid crystals, and the third electrodes  18  and the fourth electrodes  20  formed on the second substrate  12  serve as a common electrode. 
     When the barrier  200  is a liquid crystal display using a normally black mode of transmission, portions of the barrier on which the first electrodes  14  are located serve as light transmission portions, and portions of the barrier on which the second electrodes  16  are located serve as light interception portions during the first period T 1 . 
     When the barrier  200  is a liquid crystal display using a normally white mode of transmission, portions of the barrier on which the first electrodes  14  are located serve as light interception portions, and portions of the barrier on which the second electrodes  16  are located serve as light transmission portions during the first period T 1 . 
     Accordingly, the barrier  200  features a striped pattern such that the light transmission portions of the barrier are formed to extend along the second direction (the direction of the Y-axis in  FIGS. 12A and 12B ). 
     In the third period T 3  during which the panel displays the second image, the reference voltage is applied to the first electrodes  14  through the first connection electrode  14   a , and the driving voltage is applied to the second electrodes  16  through the second connection electrode  16   a.    
     Accordingly, during the third period T 3  in the first mode M 2 , the second electrodes  16  operate the liquid crystals, and the third electrodes  18  and the fourth electrodes  20  serve as a common electrode. 
     When the barrier  200  is a liquid crystal display using a normally black mode of transmission, portions of the barrier on which the second electrodes  16  are located serve as light transmission portions, and portions of the barrier on which the first electrodes  14  are located serve as light interception portions during the third period T 3 . 
     When the barrier  200  is a liquid crystal display using a normally white mode of transmission, portions of the barrier on which the second electrodes  16  are located serve as light interception portions, and portions of the barrier on which the first electrodes  14  are located serve as light transmission portions during the third period T 3 . 
     Accordingly, in the third period T 3 , a pattern of the light transmission portions and the light interception portions is formed that is opposite to the pattern of the light transmission portions and the light interception portions formed in the first period T 1 . 
     In this way, the array of pixels formed on the panel and the pattern formed of the electrodes on the barrier correspond to each in the first period T 1  and in the third period T 3 . 
     According to the operation of the panel and the barrier, the left eye of a user sees the image displayed by the first pixel rows  34  during the first period T 1 , and sees the image displayed by the second pixel rows  36  during the third period T 3 . 
     Furthermore, the right eye of the user sees the image displayed by the second pixel rows  36  during the first period T 1 , and sees the image displayed by the first pixel rows  34  during the third period T 3 . Accordingly, the user can see a three-dimensional image having a resolution that is equal to a resolution of a 2D image. 
     As described above, the three-dimensional display device according to an exemplary embodiment of the present invention can provide both a portrait-type view and a landscape-type view, and can also provide a three-dimensional image of a high resolution. 
     While the present invention has been described in connection with certain 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, and equivalents thereof.