Abstract:
The present invention provides a display device including a first block including a first primary color pixel and a second primary color pixel having substantially a same area, a second block alternatingly disposed with the first block along the first direction, the second block including a third primary color pixel, a fourth primary color pixel and a white pixel. The first block and the second block have substantially a same area and the third primary color pixel has an area wider than the fourth primary color pixel and the white color pixel.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to and the benefit of Korean Patent Application No. 10-2013-0003440 filed in the Korean Intellectual Property Office on Jan. 11, 2013, the entire contents of which are incorporated herein by reference. 
     BACKGROUND 
     (a) Technical Field 
     Embodiments of the present invention relate to a display device and a driving method. 
     (b) Description of the Related Art 
     To increase light transmission efficiency in a liquid crystal display, a display device having an RGBW pixel structure, adding a white pixel to red, green, and blue pixels, has been suggested. Compared to a conventional RGB pixel structure, the RGBW pixel structure shows a light transmission efficiency of more than double the conventional RGB pixel structure such that power consumption of the RGBW pixel structure may be largely reduced. Accordingly, this structure may be appropriately applied to a mobile device. 
     However, while adding the white pixel, relative areas of the other color pixels are reduced such that the simultaneous contrast ratio is simultaneously deteriorated. That is, the RGB pixel structure has a yellow luminance of about 90% compared with the white luminance. However, in the RGBW pixel structure, the yellow luminance is only about 45% compared with the white luminance such that color quality is deteriorated. 
     The above information disclosed in this Background section is only for enhancement of understanding of the technical background and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. 
     SUMMARY 
     An exemplary embodiment of the present invention provides a display device having high luminance and excellent color quality. 
     A display device according to an exemplary embodiment of the present invention may include a first block including a first primary color pixel and a second primary color pixel having substantially a same area, a second block alternatingly disposed with the first block along the first direction, the second block including a third primary color pixel, a fourth primary color pixel and a white pixel. The first block and the second block have substantially a same area and the third primary color pixel has an area wider than the fourth primary color pixel and the white color pixel. 
     The first primary color pixel may be a red pixel, the second primary color pixel may be a green pixel, the third primary color pixel may be one of a yellow, a cyan and a magenta pixel, and the fourth primary color pixel may be a blue pixel. 
     An area of the third primary color pixel may be more than 50% of that of the second block. 
     The first primary color pixel and the second primary color pixel may be elongated along a second direction perpendicular to the first direction and the third primary color pixel may be elongated along the first direction. 
     The fourth primary color pixel and the white pixel may have substantially a same area. 
     The first block and the second block may be alternatingly disposed along a second direction. 
     The display device may further include a gate lines including a first gate line, a second gate line, a third gate line, and a data lines including a first data line, second data line, a third data line, a fourth data line and a fifth data line. A first block row is disposed between the first gate line and a second gate line and a second block row is disposed between the second gate line and the third gate line. One of the first primary color pixel and the second primary color pixel is disposed between the first data line and the second data line, the other of the first primary color pixel and the second primary color pixel is disposed between the second data line and the third data line, the third primary color pixel is disposed between the third data line and the fifth data line, one of the fourth primary color pixel and the white pixel is disposed between the fourth data line and the fifth data line, and the other of the fourth primary color pixel and the white pixel is disposed between the fourth data line and the fifth data line. The first primary color pixel, the second primary color pixel and the third primary color pixel in a first block row are connected to the second data line, the third data line and the fourth data line, respectively. One of the fourth primary color pixel and the white pixel in a first block row is connected to the fourth data line and the other of the fourth primary color pixel and the white pixel in a first row is connected to the fifth data line. The first primary color pixel, the second primary color pixel and the third primary color pixel in a second block row are connected to the fourth data line, the fifth data line and the first data line, respectively. One of the fourth primary color pixel and the white pixel in a second block row is connected to the first data line, and the other of the fourth primary color pixel and the white pixel in a second row is connected to the second data line. Odd numbered data lines supply a positive data voltage with respect to a common voltage and even numbered data lines supply a negative data voltage with respect to the common voltage. 
     A driving method of a display device according to an exemplary embodiment of the present invention may be applied to a display device including a plurality of red pixels, a plurality of green pixels, a plurality of blue pixels, a plurality of white pixels, and a plurality of fifth pixels emitting a different color from the red pixel, the green pixel, the blue pixel, and the white pixel, and the method includes applying an image signal voltage for the fifth pixel of a predetermined position and fifth pixels disposed in four diagonal directions with respect to the fifth pixel of the predetermined position to have opposite polarities. 
     The image signal voltage may be applied to the plurality of red pixels, the plurality of green pixels, the plurality of blue pixels, and the plurality of white pixels for the pixel of a predetermined position and pixels disposed in four diagonal directions with respect to the pixel of the predetermined position to have opposite polarities for each color. 
     The display device may further include a plurality of gate lines extending in a first direction and a plurality of data lines extending in a second direction, and when a region occupied by the red pixel and the green pixel adjacent to each other is referred to as a first block and a region occupied by the blue pixel, the white pixel, and the fifth pixel is referred to as a second block, the first block and the second block may be alternately disposed in a right and left direction thereby forming a block row, and may be alternately disposed in an up and down direction thereby forming a block column, first to third gate lines may be disposed for the first block row and the second block row adjacent to each other, the first gate line may be connected to the red pixel, the green pixel, the blue pixel, and the white pixel of the first block row, the second gate line may be connected to the blue pixel and the white pixel of the second block row and the fifth pixel of the first block row, the third gate line may be connected to the fifth pixel, the red pixel, and the green pixel of the second block row, the red pixel, the green pixel, the blue pixel, and the white pixel of the first block row may be connected to the data line disposed at the right side thereof, the fifth pixel of the first block row may be connected to the data line crossing it, the red pixel, the green pixel, the blue pixel, the white pixel, and the fifth pixel of the second block row may be connected to the data line disposed at the left side thereof, and data lines adjacent to each other may be applied with a signal voltage of a polarity opposite to each other. 
     According to an exemplary embodiment of the present invention, the yellow, cyan, or magenta pixel compensates the luminance deterioration of the different pixels due to the white pixel such that the display quality of the display device may be improved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a pixel layout view of a display device according to an exemplary embodiment of the present invention. 
         FIG. 2  is a layout view of a connection relation of a thin film transistor, a gate line, and a data line in the display device of  FIG. 1 . 
         FIG. 3  is a pixel layout view of a display device according to another exemplary embodiment of the present invention. 
         FIG. 4  is a layout view of a connection relation of a thin film transistor, a gate line, and a data line in the display device of  FIG. 3 . 
         FIG. 5  is a pixel layout view of a display device according to another exemplary embodiment of the present invention. 
         FIG. 6  is a layout view of a connection relation of a thin film transistor, a gate line, and a data line in the display device of  FIG. 5 . 
         FIG. 7  and  FIG. 8  are pixel layout views of a display device according to an exemplary embodiment of the present invention, showing a polarity arrangement of same color pixels. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Embodiments of the present invention will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. 
     A pixel layout view of a display device according to an exemplary embodiment of the present invention will be described with reference to  FIG. 1 . 
       FIG. 1  is a pixel layout view of a display device according to an exemplary embodiment of the present invention. 
     Referring to  FIG. 1 , a display device according to an exemplary embodiment of the present invention includes a yellow pixel  15  as well as a red pixel  11 , a green pixel  12 , a blue pixel  13 , a white pixel  14 . The red pixel  11  and the green pixel  12  have a vertically long rectangular shape, the blue pixel  13  and the white pixel  14  have a shape near a square while reducing a length of a vertical direction compared with the red pixel  11  and the green pixel  12 , and the yellow pixel  15  has a horizontally long rectangular shape. The yellow pixel  15  is disposed in a space formed by reducing the length of the vertical direction of the blue pixel  13  and the white pixel  14 . The position and the shape of the yellow pixel  15  may be variously changed. For example, the yellow pixel  15  may be disposed with a vertically long rectangular shape in a space formed by reducing a horizontal width of the white pixel  14  or the blue pixel  13 . Also, the shape of the yellow pixel  15  may be variously changed along with the shapes of the red pixel  11 , the green pixel  12 , the blue pixel  13 , and the white pixel  14 . 
     When a region occupied by the red pixel  11  and the green pixel  12  is referred to as a first block and a region occupied by the blue pixel  13 , the white pixel  14 , and the yellow pixel  15  is referred to as a second block, the first block and the second block may have a shape near a square. The first block and the second block may have the vertically or horizontally long rectangular shape. Also, the first block and the second block may have different sizes. In the present exemplary embodiment, the first block and the second block are alternately disposed in the horizontal direction thereby forming a block row, and are also alternately disposed in the vertical direction thereby forming a block column. Accordingly, the second blocks are disposed at the upper/lower and right/left sides of the first block, and the first blocks are disposed at the upper/lower and right/left sides of the second block. 
     Referring to  FIG. 2 , a connection relation of a thin film transistor, a gate line, and a data line will be described in a display device according to an exemplary embodiment of the present invention. 
       FIG. 2  is a layout view of a connection relation of a thin film transistor, a gate line, and a data line in the display device of  FIG. 1 . In  FIG. 2 , for a simplification, pixel electrodes in a first bloc row  31 ,  32 ,  33 ,  34 ,  35  are shown to be quadrangular, and only switching thin film transistors in a first block row  21 ,  22 ,  23 ,  24 ,  25 , gate lines G 1 , G 2 , G 3 , . . . and data lines D 1 , D 2 , D 3 , . . . are shown among several constituent elements of the pixel. 
     Referring to  FIG. 2 , three gate lines G 1 , G 2 , G 3 , . . . are disposed per every two block rows, and two data lines D 1 , D 2 , . . . are disposed per every one block column. Two gate lines Gland G 3  are disposed at an upper side and a lower side of the two block rows, respectively and one gate line G 2  is disposed between the two block rows. The data lines D 1 , D 2 , D 3 , . . . are disposed at the right side of the red pixel  11 , the green pixel  12 , the blue pixel  13 , and the white pixel  14 . The odd numbered data lines D 1 , D 3 , . . . disposed at the right side of the red pixel  11  and the blue pixel  13  cross the pixel electrode  35  of the yellow pixel  15  formed along the horizontal direction. 
     The gate line G 1  disposed at the upper side of the two block rows is connected to the red pixel  11 , the green pixel  12 , the blue pixel  13 , and the white pixel  14  in the first block row. That is, the gate line G 1  disposed at the upper side of the two block rows is connected to a control terminal (a gate electrode) of the thin film transistors for the red pixel  21 , the green pixel  22 , the blue pixel  23 , and the white pixel  24  in the first block row. The gate line G 2  disposed between two block rows is connected to a blue pixel and a white pixel in the second block row and a yellow pixel  15  in the first block row. That is, the gate line G 2  disposed between two block rows is connected to the control terminal of the thin film transistors for a blue pixel, a white pixel in the second block row and a yellow pixel in the first block row. The gate line G 3  disposed at the lower side of the two block rows is connected to a yellow pixel, a red pixel, and a green pixel in the second block row. That is, the gate line G 3  disposed at the lower side of two block rows is connected to the control terminal of the thin film transistor of a yellow pixel, a red pixel, and a green pixel in the second block row. 
     The red pixel  11 , the green pixel  12 , the blue pixel  13 , and the white pixel  14  in the first block row are connected to the data lines D 1 , D 2 , D 3  and D 4  . . . disposed at the right side of the pixels, respectively. That is, the source terminal of the thin film transistors  21 ,  22 ,  23 , and  24  of the red pixel  11 , the green pixel  12 , the blue pixel  13 , and the white pixel  14  are connected to the data lines D 1 , D 2 , D 3  and D 4  disposed at the right side, respectively. The drain terminal is connected to each of the pixel electrodes  31 ,  32 ,  33 , and  34 . The blue pixel and the white pixel in the second block row are connected to the data lines D 1  and D 2  disposed at the right side, respectively. That is, the source electrodes of the thin film transistors of the blue pixel and the white pixel in the second block row are connected to the data lines D 1  and D 2  disposed at the right side, respectively. The drain terminals of a thin film transistor in the blue pixel and the white pixel in the second block row are connected to each of the pixel electrodes. The red pixel and the green pixel in the second block row are connected to the data lines D 3  and D 4  disposed at the left side of the pixels. That is, the source electrodes of the thin film transistors of the red pixel and the green pixel in the second block row are connected to the data lines D 2  and D 3  disposed at the left side of the pixels. The drain terminals of the red pixel and the green pixel in the second block row are connected to each of the pixel electrodes. The yellow pixel is connected to odd numbered data lines D 1  and D 3  crossing the yellow pixel itself in the vertical direction. That is, the source electrode of the thin film transistor of the yellow pixel is connected to the data lines D 1  and D 3  crossing the yellow pixel electrode in the vertical direction, and the drain electrode of the yellow pixel is connected to the yellow pixel electrode. 
     In the above, the exemplary embodiment including the yellow pixel  15  as well as the red pixel  11 , the green pixel  12 , the blue pixel  13 , and the white pixel  14  was described. However a cyan pixel or a magenta pixel instead of the yellow pixel  15  may be included. 
     In the display device of this structure, if column inversion driving is performed, the polarity of the pixel is arranged as shown in  FIG. 1 . That is, an image signal voltage having opposite polarities is applied to the neighboring data lines. 
     As described above, if the yellow pixel, the cyan pixel, or the magenta pixel is disposed as well as the red pixel, the green pixel, the blue pixel, and the white pixel, the yellow pixel, the cyan pixel, or the magenta pixel compensates the luminance deterioration of the other color pixels due to the white pixel, thereby improving the display quality of the display device. 
       FIG. 3  is a pixel layout view of a display device according to another exemplary embodiment of the present invention, and  FIG. 4  is a layout view of a connection relation of a thin film transistor, a gate line, and a data line in the display device of  FIG. 3 . 
     The display device of  FIG. 3  and  FIG. 4  includes a different connection state of the thin film transistor for the yellow (or the cyan or magenta) pixel and the data lines D 0 , D 3 , . . . from the display device of  FIG. 1  and  FIG. 2 , and thereby the polarity arrangement of the yellow (or the cyan or magenta) pixel  15  is changed. 
     In the display device of  FIG. 3  and  FIG. 4 , the data line D 0  of the left side of the first pixel column is additionally disposed. The thin film transistor of the yellow pixel in the odd-numbered block column is connected to the data line D 0  disposed at the left side of the yellow pixel, and the thin film transistor  25  of the yellow pixel  15  included in the even-numbered block column is connected to the data line D 3  crossing it in the horizontal direction. 
     In the display device of the this structure, if column inversion driving is performed, as shown in  FIG. 3 , the yellow pixel  15  of the positive polarity and the yellow pixel  15  of the negative polarity are uniformly and symmetrically distributed on the entire screen. 
       FIG. 5  is a pixel layout view of a display device according to another exemplary embodiment of the present invention, and  FIG. 6  is a layout view of a connection relation of a thin film transistor, a gate line, and a data line in the display device of  FIG. 5 . 
     The display device of  FIG. 5  and  FIG. 6  includes a different connection state of the blue pixel  13  and the white pixel  14  included in the even-numbered block row and the data lines D 0  and D 1  from the display device of  FIG. 3  and  FIG. 4 , and thereby the polarity arrangement of the blue pixel  13  and the white pixel  14  is changed. 
     In the display device of  FIG. 5  and  FIG. 6 , the thin film transistors of the blue pixel and the white pixel included in the even-numbered block columns are respectively connected to the data lines D 0  and D 1  disposed at the left side thereof, and the thin film transistors of the blue pixel and the white pixel in the even-number block columns are respectively connected to the data lines D 3  and D 4  disposed at the right side thereof. 
     In the display device of the this structure, if the column driving is performed, as shown in  FIG. 5 , the blue pixel and the white pixel  14  of the positive polarity and the blue pixel and the white pixel of the negative polarity are uniformly and symmetrically distributed on the entire screen. 
     As described above, if the pixels are disposed and the column inversion driving is performed, as shown in  FIG. 7  and  FIG. 8 , the overall polarity arrangement of the red pixel, the green pixel, the blue pixel, the white pixel, and the yellow (or the cyan or magenta) pixel is radial-symmetrical on the entire screen such that the display deterioration such as a flicker of a longitudinal or a transverse line may be prevented. That is, for each color, the polarity of the pixel of any one position is driven to be opposite to the polarity of the pixels disposed in the four diagonal directions such that the display quality may be improved. 
     Table 1 below shows a change of a luminance ratio (Y/W) of a white color and a yellow color according to an area of a yellow pixel when applying an exemplary embodiment of the present invention to the liquid crystal display. A Y area means a ratio of an area occupied by a yellow pixel in the second block of the region occupied with the blue pixel, the white pixel, and the yellow pixel. 
     
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                   
                 White 
                 Yellow 
                   
               
               
                   
                 Y area 
                 luminance 
                 luminance 
                 Y/W (%) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 RGB structure 
                   
                 100 
                 90 
                 90 
               
               
                 RGBW structure 
                   
                 200 
                 90 
                 45 
               
               
                 An embodiment of 
                 1 
                 180 
                 180 
                 100 
               
               
                 the present 
                 0.9 
                 182 
                 171 
                 94 
               
               
                 invention 
                 0.8 
                 184 
                 162 
                 88 
               
               
                   
                 0.7 
                 186 
                 153 
                 82 
               
               
                   
                 0.6 
                 188 
                 144 
                 77 
               
               
                   
                 0.5 
                 190 
                 135 
                 71 
               
               
                   
                 0.4 
                 192 
                 126 
                 66 
               
               
                   
                 0.3 
                 194 
                 117 
                 60 
               
               
                   
                 0.2 
                 196 
                 108 
                 55 
               
               
                   
                 0.1 
                 198 
                 99 
                 50 
               
               
                   
                 0 
                 200 
                 90 
                 45 
               
               
                   
               
             
          
         
       
     
     As shown in Table 1, if the area occupied by the yellow pixel in the second block is more than half, the luminance ratio (Y/W) of the yellow color for the while color is over 70%. However, a human eye recognizes a yellow degradation when the luminance ratio (Y/W) of the yellow color for the white color is less than 70%. Accordingly, to prevent this, it may be determined that the area occupied with the yellow pixel in the second block is more than half. 
     The described display device may be applied to an organic light emitting device or a plasma display device as well as the liquid crystal display. 
     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.