Abstract:
A pixel arrangement structure for an organic light emitting display including a plurality of sub-pixel groups repeatedly arranged, wherein each of the sub-pixel groups includes: four first sub-pixels for emitting light of a first color and each having a hexagonal structure, two second sub-pixels for emitting light of a second color and each including two hexagonal structures sharing one side, and two third sub-pixels for emitting light of a third color and each including two hexagonal structures sharing one side. Two of the four first sub-pixels are arranged in a same column and share a symmetrical axis, and the two second sub-pixels and the two third sub-pixels are alternately arranged on either side of the symmetrical axis.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to and the benefit of Korean Patent Application No. 10-2009-0063932, filed on Jul. 14, 2009, in the Korean Intellectual Property Office, the entire content of which is incorporated herein by reference. 
     BACKGROUND 
     1. Field 
     The following description relates to a pixel arrangement structure for an organic light emitting display. 
     2. Description of the Related Art 
     An organic light emitting display displays an image using an organic light emitting diode (OLED) for emitting light. OLEDs have high brightness and chromatic purity, thereby contributing to the organic light emitting display as being a next generation display. 
     The organic light emitting display consists of a plurality of pixels including red sub-pixels, green sub-pixels, and blue sub-pixels, to display various color images. 
     The red sub-pixels, the green sub-pixels, and the blue sub-pixels may be arranged in various forms, such as a stripe form, a mosaic form, and a delta form. 
     In the stripe form, sub-pixels of the same color are arranged in units of columns. In the mosaic form, the red sub-pixels, the green sub-pixels, and the blue sub-pixels are sequentially arranged in both column and row directions. In the delta form, the red sub-pixels, the blue sub-pixels, and the green sub-pixels are sequentially arranged so that the sub-pixels are arranged in a zig-zag form. 
     In addition, “ClairVoyante Laboratories” suggested a pixel arrangement structure named “the Pentile Matrix Color Pixel Arrangement”. When “the Pentile Matrix Color Pixel Arrangement” is applied, relatively high resolution display ability is obtained and, although resolution is not exceptionally high, vertical line patterns caused by specific pixels are not visualized, such that picture characteristics can be improved. 
     SUMMARY OF THE INVENTION 
     Accordingly, exemplary embodiments of the present invention provide a pixel arrangement structure for an organic light emitting display for securing a desired aperture ratio while displaying high resolution. 
     In one exemplary embodiment of the present invention, there is provided a pixel arrangement structure for an organic light emitting display including a plurality of sub-pixel groups repeatedly arranged. Each of the sub-pixel groups includes: four first sub-pixels for emitting light of a first color and each having a hexagonal structure, two second sub-pixels for emitting light of a second color and each including two hexagonal structures sharing one side, and two third sub-pixels for emitting light of a third color and each including two hexagonal structures sharing one side. Two of the four first sub-pixels are arranged in a same column and share a symmetrical axis. The two second sub-pixels and the two third sub-pixels are alternately arranged on either side of the symmetrical axis. 
     The first sub-pixels may be green sub-pixels, the second sub-pixels may be red sub-pixels, and the third sub-pixels may be blue sub-pixels. 
     The symmetrical axis may pass through corners of the two of the four first sub-pixels. A second sub-pixel of the two second sub-pixels and a corresponding third sub-pixel of the two third sub-pixels in a same row may be arranged to be symmetrical with each other along the symmetrical axis. 
     The first sub-pixels of the plurality of sub-pixel groups may be arranged in a zig-zagging arrangement. 
     The two second sub-pixels of each of the sub-pixel groups may be arranged to have different axes of symmetry. Each of the two third sub-pixels of each of the sub-pixel groups may be in a same column as a corresponding one of the two second sub-pixels and may be arranged in a same direction as the corresponding second sub-pixel in the same column. 
     In the repeatedly arranged pattern of the plurality of sub-pixel groups, a number of the first sub-pixels may correspond to a resolution of the organic light emitting display, and a number of the second sub-pixels and a number of the third sub-pixels may correspond to half of the resolution of the organic light emitting display. 
     When a “Pentile Matrix Color Pixel Arrangement” is formed by using square-shaped sub-pixels, an optimal or desired aperture ratio may be difficult to realize. According to exemplary embodiments of the present invention, by modifying the “Pentile Matrix Color Pixel Arrangement” by utilizing hexagonal sub-pixels or sub-pixels having a modified structure based on a hexagonal structure, a desired aperture ratio may be more readily achieved. Additionally, efficiency and life of the OLED display, as well as image sticking of the OLED display, may be improved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, together with the specification, illustrate exemplary embodiments of the present invention, and, together with the description, serve to explain the principles of the present invention. 
         FIG. 1  is a plan view illustrating a pixel arrangement structure according to an embodiment of the present invention; 
         FIG. 2  is an enlarged plan view illustrating the sub-pixel group of  FIG. 1 ; 
         FIG. 3  is a plan view illustrating an example of a color arrangement that may be applied to the sub-pixel group of  FIG. 2 ; and 
         FIG. 4  is a plan view illustrating another example of a color arrangement that may be applied to the sub-pixel group of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following detailed description, only certain exemplary embodiments of the present invention have been shown and described by way of illustration. As those skilled in the art will recognize, the described embodiments may be modified in various different ways without departing from the spirit or scope of the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive. In addition, when an element is referred to as being “on” another element, it may be directly on the other element, or may be indirectly on the other element, with one or more elements interposed therebetween. Also, when an element is referred to as being “connected to” another element, it may be directly connected to the other element, or may be indirectly connected to the other element, with one or more elements interposed therebetween. Hereinafter, like reference numerals refer to like elements. 
     Hereinafter, the embodiment of the present invention will be described in detail with reference to the accompanying drawings. 
       FIG. 1  is a plan view illustrating a pixel arrangement structure according to an embodiment of the present invention.  FIG. 2  is an enlarged plan view illustrating the sub-pixel group of  FIG. 1 . 
     Referring to  FIGS. 1 and 2 , in the pixel arrangement structure according to the embodiment of the present invention, a plurality of sub-pixel groups  10  each consisting of hexagonal sub-pixels  12 ,  14 , and  16  are repeatedly arranged. 
     Here, the sub-pixel group  10  provides an arrangement of sub-pixels having a pattern that is repeated, and includes a plurality of first sub-pixels  12 , second sub-pixels  14 , and third sub-pixels  16 . 
     The first sub-pixels  12  emit light of a first color and are hexagonal. Four first sub-pixels  12  are provided in each sub-pixel group  10 . The four first sub-pixels  12  are arranged, such that two sub-pixels  12  are in a same column and share a first symmetrical axis  22 . 
     Here, the first symmetrical axis  22  passes through corners of the two first sub-pixels  12  positioned in the same column. For example, the first symmetrical axis  22  may pass through the corners of the two first sub-pixels  12  that are facing or pointed towards one another. The first sub-pixels  12  are arranged in a column direction, so that the first symmetrical axis  22  forms a continuous vertical line in an entire pixel arrangement structure (e.g., in a pattern in which a plurality of sub-pixel groups  10  are repeatedly arranged in a column direction). 
     The plurality of first sub-pixels  12  are alternately arranged, so that in the pattern where the plurality of sub-pixel groups  10  are repeatedly arranged, the first sub-pixels positioned in a first column and the first sub-pixels positioned in a second column are not positioned in the same row. For convenience, a row is based on one hexagon sub-pixel. The plurality of first sub-pixels  12  are alternately arranged, so that the first sub-pixels positioned in a first row and the first sub-pixels positioned in a second row adjacent to the first row are not positioned in the same column. That is, the plurality of first sub-pixels  12  are arranged in a zig-zagging configuration or arrangement in the entire pixel arrangement structure. 
     The second sub-pixels  14  emit light of a second color and have a structure, in which two hexagons share one side  20 . That is, the second sub-pixel  14  includes a first hexagonal region  14   a  and a second hexagonal region  14   b . Two such second sub-pixels  14  are provided in each sub-pixel group  10 . The two second sub-pixels  14  are alternately positioned in one sub-pixel group  10  in a diagonal direction, as illustrated in  FIG. 2 . 
     The third sub-pixels  16  emit light of a third color and have a structure, in which two hexagons share one side similar to the second sub-pixels  14 . That is, the third sub-pixels  16  include a first hexagonal region  16   a  and a second hexagonal region  16   b . Two such third sub-pixels  16  are provided in each sub-pixel group  10 . The two third sub-pixels  16  provided in one sub-pixel group  10  are alternately positioned in the sub-pixel group  10  in a diagonal direction, as illustrated in  FIG. 2 . The second and third sub-pixels  14  and  16  are alternately arranged, similarly to a checker board. 
     On the other hand, among the two second sub-pixels  14  and the two third sub-pixels  16  provided in one sub-pixel group  10 , the second sub-pixel  14  and the third sub-pixel  16  positioned in the same row are arranged to be linearly symmetrical with each other based on the first symmetrical axis  22 . 
     To be specific, the first hexagonal region  14   a  of the second sub-pixel  14  and the first hexagonal region  16   a  of the third sub-pixel  16  are sequentially arranged in a same row with the first sub-pixel  12  interposed. 
     The second hexagonal region  14   b  of the second sub-pixel  14  and the second hexagonal region  16   b  of the third sub-pixel  16  may be arranged in a same row, such that each of these second hexagonal regions has a side positioned along the first symmetrical axis  22 . That is, when there are no empty spaces or gaps between the sub-pixels  12 ,  14 , and  16  and the sub-pixels  12 ,  14 , and  16  are closely arranged, one side of the second hexagonal region  14   b  of the second sub-pixel  14  and one side of the second hexagonal region  16   b  of the third sub-pixel  16  may contact each other along the first symmetrical axis  22 . 
     The two second sub-pixels  14  provided in one sub-pixel group  10  are arranged in different directions so that the symmetrical axis of the two sub-pixels  14  does not coincide with each other (for example, the two second sub-pixels  14  are offset in a row direction and have rotated orientations). In addition, the two third sub-pixels  16  are arranged in different directions so that the symmetrical axis does not coincide with each other, similarly to the second sub-pixels  14 . That is, the second sub-pixel  14  and the third sub-pixel  16  are alternately arranged, similarly to a checker board, and are alternately arranged in both first and second directions. 
     The second sub-pixel  14  and/or the third sub-pixel  16  positioned in the same column are arranged in the same direction. 
     For example, each third sub-pixels  16  provided in one sub-pixel group  10  is positioned in a same column as one of the second sub-pixels  14 , and is arranged in the same direction as the second sub-pixel  14  positioned in the same column. 
     As described above, according to the embodiment of the present invention, high resolution can be displayed by utilizing “the Pentile Matrix Color Pixel Arrangement”. “The Pentile Matrix Color Pixel Arrangement” may be driven to display high resolution using, for example, the “sub-pixel rendering method,” similarly as disclosed in the Korean Patent Publication No. 2003-0086399. 
     According to an exemplary embodiment of the present invention, the sub-pixels  12 ,  14 , and  16  are formed to have a hexagonal structure or a modified structure based on a hexagon and are arranged so that dead space or gaps are minimized. Such a hexagonal structure may be optimal or assist in improving an aperture ratio. Therefore, according to the embodiment of the present invention, by securing a high aperture ratio, the efficiency and life of the OLED may be increased and the image sticking of the OLED may be improved. 
     In addition, according to the embodiment of the present invention, in the pattern where the plurality of sub-pixel groups  10  are repeatedly arranged, where a number of first sub-pixels  12  corresponds to the resolution of the display, a number of second sub-pixels  14  and a number of third sub-pixels  16  may correspond to half of the resolution of the display. 
     Here, the first sub-pixels  12  may be set as sub-pixels having a color that is more sensitive to resolution, for example, green sub-pixels, so that a high quality image can be provided. 
     The second sub-pixels  14  and the third sub-pixels  16  may be set as red sub-pixels or blue sub-pixels and are formed to have a structure, in which two hexagons are put together. In this case, since one side  20  shared by the two hexagons does not actually become a dead space unlike the boundary  18  of the sub-pixels  12 ,  14 , and  16 , it may help with securing a desired aperture ratio. 
     In the present embodiment, the area of one second sub-pixel  14  or third sub-pixel  16  is illustrated as being twice the area of one first sub-pixel  12 . However, the present invention is not limited to the above. That is, the areas of the first sub-pixel  12 , the second sub-pixel  14 , and the third sub-pixel  16  may be changed based on various factors, for example, the life of materials respectively utilized in each color sub-pixel. 
       FIG. 3  is a plan view illustrating an example of a color arrangement that may be applied to the sub-pixel group of  FIG. 2 .  FIG. 4  is a plan view illustrating another example of a color arrangement that may be applied to the sub-pixel group of  FIG. 2 . 
     First, referring to  FIG. 3 , the first sub-pixel  12  may be set as a green sub-pixel G that may be more sensitive to resolution, and the second sub-pixel  14  and the third sub-pixel  16  may respectively be set as a red sub-pixel R and a blue sub-pixel B that may be less sensitive to resolution. 
     In another embodiment as illustrated in  FIG. 4 , the first sub-pixel  12  may be set as the green sub-pixel G and the second sub-pixel  14  and the third sub-pixel  16  may be set as the blue sub-pixel B and the red sub-pixel R, respectively. 
     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 is instead intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, and equivalents thereof.