Abstract:
The present invention provides a stereoscopic image panel making it possible to freely watch a stereoscopic image by being equipped with parallax barriers, a stereoscopic image display apparatus including the stereoscopic image panel, and a method of driving the stereoscopic image panel. A stereoscopic image panel according to the present invention includes: a liquid crystal layer; a first electrode unit positioned opposite to one side of the liquid crystal layer; a second electrode unit including first, second, and third electrodes positioned such that one side of each of the electrodes is opposite the other side of the liquid crystal layer; and a third electrode unit positioned opposite the other side of the second electrode.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of priority of Korean Patent Application No. 10-2011-0107165 filed on Oct. 19, 2011, all of which is incorporated by reference in their entirety herein. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a stereoscopic image panel, a stereoscopic image display apparatus having the same, and a driving method thereof, and more particularly, to a stereoscopic image panel that provides a glasses-free stereoscopic image, an stereoscopic image display apparatus having the stereoscopic image panel, and a method of driving the stereoscopic image panel. 
         [0004]    2. Discussion of the Related Art 
         [0005]    In general, the technology related to stereoscopic image display apparatuses is used in various fields, not only in the image-related field, but the aerospace industry and the art industry, including consumer-electronics and telecommunication industries. The stereoscopic image display apparatuses largely employ glasses type and glasses-free type of stereoscopic image-generating techniques. 
         [0006]    The glasses type is classified into a coded glasses type with wavelength option, a polarized glasses type using a light blocking effect of a polarizer, and a time-division glasses type alternately providing left and right images within the time of the residual image of eyes. However, the glasses type has a problem in that it is inconvenient to put on glasses when watching a stereoscopic image and eye strain is caused in long time watching. Therefore, researches of developing a glasses-free type of stereoscopic image-generating technique have been conducted to solve such a problem as mentioned above. A method in the researches has been disclosed in Korean Patent Publication No. 2007-0023849 (2007.03.02). 
         [0007]    The published invention adopts a structure of bonding a multilayer of parallax barriers on an LCD panel. Therefore, the published invention makes it possible to adjust a watching distance and a viewing angle for a stereoscopic image display by driving only the barrier corresponding to the watching distance of a viewer. However, in the published invention, light is partially transmitted through the gaps between the micro-barrier electrodes, so that crosstalk may be generated. Therefore, the published invention may have a problem in that the quality of a stereoscopic image is deteriorated and bonding becomes difficult. 
       SUMMARY OF THE INVENTION 
       [0008]    It is an object of the present invention to provide a stereoscopic image panel making it possible to freely watch a stereoscopic image by being equipped with parallax barriers, a stereoscopic image display apparatus including the stereoscopic image panel, and a method of driving the stereoscopic image panel. 
         [0009]    To accomplish the above-mentioned objects, the present invention provides a stereoscopic image panel including: a liquid crystal layer; a first electrode unit positioned opposite to one side of the liquid crystal layer; a second electrode unit including first, second, and third electrodes positioned such that one side of each of the electrodes is opposite to the other side of the liquid crystal layer; and a third electrode unit positioned opposite to the other side of the second electrode. 
         [0010]    A plurality of the first, second, and third electrodes may be provided respectively and the end of one side of the first electrode may be positioned adjacent to the end of one side of the second electrode, and the end of the other side of the second electrode may be positioned adjacent to the end of one end of the third electrode. 
         [0011]    The first, second, and third electrodes may include transparent electrodes. 
         [0012]    Further, the present invention provides a stereoscopic image display apparatus that includes the stereoscopic image panel, including: a measuring unit that measures positional information of a viewer; a control unit that selects the first, second, and third electrodes of the stereoscopic image panel on the basis of the positional information of the viewer provided from the measuring unit; and a driving circuit unit that applies driving power to the first, second, and third electrodes selected by the control unit. 
         [0013]    The stereoscopic image display apparatus may further include an image panel that is disposed at a side of the stereoscopic image panel and reproduces images that are the base of a stereoscopic image. 
         [0014]    Further, the present invention provides a method of driving a stereoscopic image panel, which includes: a liquid crystal layer; a first electrode unit positioned opposite to one side of the liquid crystal layer; a second electrode unit including first, second, and third electrodes positioned such that one side of each of the electrodes is opposite to the other side of the liquid crystal layer; and a third electrode unit positioned opposite to the other side of the second electrode, includes changing the state of the liquid crystal layer by selectively applying a driving voltage to at least one or more of the firte, second, and third electeodes. 
         [0015]    The first, second, and third electrodes may include transparent electrodes. 
         [0016]    A plurality of the first, second, and third electrodes may be provided, respectively, the end of one side of the first electrode may be positioned adjacent to the end of one side of the second electrode, and the end of the other side of the second electrode may be positioned adjacent to the end of one end of the third electrode. 
         [0017]    The method of driving a stereoscopic image panel may further include: in a case that the liquid crystal layer is configured to block light when an electric field is formed, and to transmit light when the electric field is not formed in the liquid crystal layer, a) forming a first state transition in the liquid crystal layer by applying the driving voltage between the first electrode unit and the third electrode and by generating a short circuit between the first electrode unit and the second electrode; b) forming a second state transition in the liquid crystal layer by applying the driving voltage between the first electrode unit and the third electrode and by generating a short circuit between the first electrode unit and the third electrode; and c) forming a third state transition in the liquid crystal layer by applying the driving voltage between the first electrode unit and the third electrode and by generating a short circuit between the first electrode unit and the first electrode. 
         [0018]    The method of driving a stereoscopic image panel may further include: in a case that the liquid crystal layer is configured to transmit light when an electric field is formed, and to block light when the electric field is not formed in the liquid crystal layer, a) forming a first state transition in the liquid crystal layer by applying the driving voltage between the first electrode unit and the second electrode; b) forming a second state transition in the liquid crystal layer by applying the driving voltage between the first electrode unit and the third electrode; and c) forming a third state transition in the liquid crystal layer by applying the driving voltage between the first electrode unit and the first electrode. 
         [0019]    According to a stereoscopic image panel, a stereoscopic image display apparatus including the stereoscopic image panel, and a method of driving the stereoscopic image pane of the present invention, it is possible to implement a smooth and free stereoscopic image by minimizing discontinuity generated when moving a barrier and minimizing crosstalk. 
         [0020]    Further, the technical effect of the present invention described above is not limited to the effect described above and other technical effects not stated herein can be clearly understood by those skilled in the art from the following description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings: 
           [0022]      FIG. 1  is a configuration diagram showing a stereoscopic image display apparatus according to an exemplary embodiment of the present invention; 
           [0023]      FIG. 2  is a configuration diagram showing the structure of the stereoscopic image panel according to the exemplary embodiment; 
           [0024]      FIGS. 3A to 3C  are configuration diagrams showing a transition state of a stereoscopic image panel according to another exemplary embodiment of the present invention; and 
           [0025]      FIGS. 4A to 4C  are configuration diagrams showing a transition state of a stereoscopic image panel according to another exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0026]    Hereinafter, a stereoscopic image display apparatus according to an exemplary embodiment of the present invention and a driving method thereof will be described in detail with reference to the accompanying drawings. 
         [0027]      FIG. 1  is a configuration diagram showing a stereoscopic image display apparatus according to an exemplary embodiment of the present invention. 
         [0028]    As shown in  FIG. 1 , a stereoscopic image display apparatus includes a measuring unit  100 , a control unit  200 , a driving circuit unit  300 , an image panel  400 , and a stereoscopic image panel  500 . 
         [0029]    The measuring unit  100  is provided to measure the positional information of a viewer, such as the distance from the viewer, the left and right positions, and face inclination. A measuring sensor and a camera may be used as the measuring unit  100 . For example, an IR (Infrared Ray), ultrasonic waves or a laser sensor may be selectively used as the measuring sensor, and a regular camera such as a 2D camera and a stereo-camera may be selectively used as the camera. 
         [0030]    The control unit  200  selects electrode units  520 ,  530 , and  540  (see  FIG. 2 ) of the stereoscopic image panel  500  on the basis of the positional information of the viewer transmitted from the measuring unit  100 . Further, the driving circuit unit  300  is provided to apply a driving voltage Vb to the electrode units  520 ,  530 , and  540  selected by the control unit  200 . 
         [0031]    The image panel  400  may be a general display in order to reproduce an image in a pixel unit. The image panel  400  is positioned ahead of a backlight  410 . The image panel  400  includes an image panel  420  composed of right eye pixels R that are shown to the viewer&#39;s right eye and left eye pixels L that are shown to the viewer&#39;s left eye. 
         [0032]      FIG. 2  is a configuration diagram showing the structure of the stereoscopic image panel according to the exemplary embodiment. 
         [0033]    As shown in  FIG. 2 , the stereoscopic image panel  500  according to the exemplary embodiment is positioned at a side of the image panel  400 . The stereoscopic image panel  500  is provided to provide a viewer with a stereoscopic image on the basis of the images provided from the image panel  400 . The stereoscopic image panel  500  may include a liquid crystal layer  510 , a first electrode unit  520 , a second electrode unit  530 , and a third electrode unit  540 . 
         [0034]    The liquid crystal layer  510  blocks or transmits the image reproduced from the image panel  400 . The liquid crystal layer  510  may be used in a (normally black) way of transmitting light when a predetermined electric field is generated and of blocking light when an electric field is not generated, and a (normally white) way of blocking light when a predetermined electric field is generated and of transmitting light when an electric field is not generated in the liquid crystal layer  510 . 
         [0035]    The first electrode unit  520  is disposed at a side of the liquid crystal layer  510 . The first electrode unit  520  may be positioned with one side opposite the liquid crystal layer  510  throughout the entire area of the liquid crystal layer  510 . 
         [0036]    The second electrode unit  530  is positioned opposite the liquid crystal layer  510 , on the other side opposite the side where the first electrode unit  520  is positioned, with respect to the liquid crystal layer  510 . The second electrode unit  530  includes first, second, and third electrodes  531 ,  532 , and  533 . The first, second, and third electrodes  531 ,  532 , and  533  are positioned such that one side of each of the electrodes is opposite the liquid crystal layer  510  throughout the liquid crystal layer  510 . A plurality of first, second, and third electrodes  531 ,  532 , and  533  may be alternately disposed. For example, the end of one side of the first electrode  531  may be positioned adjacent to the end of one side of the second electrode  532  and the end of the other side of the second electrode  532  may be positioned adjacent to the end of one end of the third electrode  533 . 
         [0037]    The third electrode unit  540  is positioned opposite the other side of the second electrode unit  530  having one side opposite the liquid crystal layer  510 . Further, the third electrode unit  540  may be positioned opposite the liquid crystal layer  510  throughout the entire area of the liquid crystal layer  510 . 
         [0038]    The first, second, and third electrode units  520 ,  530 , and  540  may be implemented by ITO (Indium Tin Oxide) transparent electrodes. Further, although the exemplary embodiment describes when the second electrode unit  530  is positioned between the liquid crystal layer  510  and the third electrode unit  540 , the second electrode unit  530  may be positioned between the liquid crystal layer  510  and the first electrode unit  520 , in accordance with embodiments. 
         [0039]    The operational state of the stereoscopic image panel according to the exemplary embodiment is described hereafter in detail with reference to the accompanying drawings. The (normally white) way of blocking light when a predetermined electric field is generated in a liquid crystal layer and of transmitting light when an electric field is not generated is exemplified in the following description. 
         [0040]      FIGS. 3A to 3C  are configuration diagrams showing a transition state of the stereoscopic image panel according to the exemplary embodiment of the present invention. 
         [0041]    As shown in  FIGS. 3A to 3C , the stereoscopic image panel  500  may have three state transitions in accordance with the driving voltage Vb 1  applied to the first, second, and third electrode units  520 ,  530 , and  540 . A driving method of three state transitions of the stereoscopic image panel  500  is described in detail with reference to the following Table 1. 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 DLPB operation 
                   
               
               
                   
                 state 
                 Driving circuit operated 
               
               
                   
                   
               
             
             
               
                   
                 State 1 
                 s1-s5: driving voltage (Vd1) 
               
               
                   
                   
                 applied 
               
               
                   
                   
                 s1-s3: short 
               
               
                   
                 State 2 
                 s1-s5: driving voltage (Vd1) 
               
               
                   
                   
                 applied 
               
               
                   
                   
                 s1-s4: short 
               
               
                   
                 State 3 
                 s1-s5: driving voltage (Vd1) 
               
               
                   
                   
                 applied 
               
               
                   
                   
                 s1-s2: short 
               
               
                   
                   
               
             
          
         
       
     
         [0042]    In Table 1, s 1  indicates connection between the driving circuit unit  300  and the first electrode unit  520 , s 2  indicates connection between the driving circuit unit  300  and the first electrode  531 , s 3  indicates connection between the driving circuit unit  300  and the second electrode  532 , s 4  indicates connection between the driving circuit unit  300  and the third electrode  533 , and s 5  indicates connection between the driving circuit unit  300  and the third electrode unit  540   
         [0043]      FIG. 3A  is a diagram showing a first state (State  1 ) of the stereoscopic image panel according to the exemplary embodiment. The first state is implemented, when a driving voltage Vb 1  is applied between s 1  and s 5  and a short circuit is generated between s 1  and s 3 . 
         [0044]      FIG. 3B  is a diagram showing a second state (State  2 ) of the stereoscopic image panel according to the exemplary embodiment. The second state is implemented, when the driving voltage Vb 1  is applied between s 1  and s 5  and a short circuit is generated between s 1  and s 4 . 
         [0045]      FIG. 3C  is a diagram showing a third state (State  3 ) of the stereoscopic image panel according to the exemplary embodiment. The third state is implemented, when the driving voltage Vb 1  is applied between s 1  and s 5  and a short circuit is generated between s 1  and s 2 . 
         [0046]    It can be seen from  FIGS. 3A to 3C  that even if the driving voltage Vb 1  is applied to the first, second, and third electrode units  520 ,  530 , and  540  such that light is blocked throughout the entire area of the liquid crystal layer  510  in the stereoscopic image panel  500 , the voltage differences at sections between the first electrode unit  520  and the first, second, and third electrodes  531 ,  532 , and  533  respectively connected with the driving circuit unit  300  are 0, so that an electric field is not generated in the liquid crystal layer  510  and light can be transmitted. 
         [0047]    The short circuit means connection of both terminals through a circuit or an equivalent potential state in the present invention. The most typical method of making the equivalent potential state is to ground both terminals through a circuit. 
         [0048]    The operational state of a stereoscopic image panel according to another exemplary embodiment is described hereafter in detail with reference to the accompanying drawings. The (normally black) way of transmitting light when a predetermined electric field is generated layer and of blocking light when an electric field is not generated in a liquid crystal layer is exemplified in the following description. 
         [0049]      FIGS. 4A to 4C  are configuration diagrams showing a transition state of a stereoscopic image panel according to another exemplary embodiment of the present invention. 
         [0050]    As shown in  FIGS. 4A to 4C , a stereoscopic image panel  500  according to another exemplary embodiment may have three state transitions in accordance with the driving voltage Vb 1  applied to the first, second, and third electrode units  520 ,  530 , and  540 . A driving method of three state transitions of the stereoscopic image panel  500  is described in detail with reference to the following Table 2. 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 DLPB operation 
                   
               
               
                   
                 state 
                 Driving circuit operated 
               
               
                   
                   
               
             
             
               
                   
                 State 1 
                 s1-s3: driving voltage (Vd1) 
               
               
                   
                   
                 applied 
               
               
                   
                 State 2 
                 s1-s4: driving voltage (Vd1) 
               
               
                   
                   
                 applied 
               
               
                   
                 State 3 
                 s1-s2: driving voltage (Vd1) 
               
               
                   
                   
                 applied 
               
               
                   
                   
               
             
          
         
       
     
         [0051]    In Table 2, s 1  indicates connection between the driving circuit unit  300  and the first electrode unit  520 , s 2  indicates connection between the driving circuit unit  300  and the first electrode  531 , s 3  indicates connection between the driving circuit unit  300  and the second electrode  532 , s 4  indicates connection between the driving circuit unit  300  and the third electrode  533 , and s 5  indicates connection between the driving circuit unit  300  and the third electrode unit  540 . 
         [0052]      FIG. 4  is a diagram showing a first state (State  1 ) of the stereoscopic image panel according to another exemplary embodiment. The first state is implemented, when the driving voltage Vb 1  is applied between s 1  and s 3 . 
         [0053]      FIG. 4  is a diagram showing a second state (State  2 ) of the stereoscopic image panel according to another exemplary embodiment. The second state is implemented, when the driving voltage Vb 1  is applied between s 1  and s 4 . 
         [0054]      FIG. 4  is a diagram showing a third state (State  3 ) of the stereoscopic image panel according to another exemplary embodiment. The third state is implemented, when the driving voltage Vb 1  is applied between s 1  and s 2 . 
         [0055]    As described above, the stereoscopic image panel, a stereoscopic image display apparatus including the stereoscopic image panel, and a method of driving the stereoscopic image panel according to the present invention, since the transmitting area and the blocking area of the liquid crystal layer  510  transit into the third state in accordance with the driving voltage Vb 1  applied to the first, second, and third electrode units  520 ,  530 , and  540  by the driving circuit unit  300 , can provide a continuous glasses-free stereoscopic image in accordance with changes in position and watching distance of a viewer. 
         [0056]    The embodiments of the present invention which are described above and illustrated in the drawings should not be construed as limiting the spirit of the present invention. The protection scope of the present invention is limited only by claims and the present invention may be modified in various ways by those skilled in the art without departing from the scope of the present invention. Therefore, the changes and modifications will be included in the protection scope of the present invention, as long as those are apparent to those skilled in the art.