Patent Publication Number: US-9887247-B2

Title: Sub-pixel arrangement structure of organic light emitting diode display

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to flat display technology, in particular, to a sub-pixel arrangement structure of an organic light emitting diode (OLED) display. 
     2. Description of Related Art 
     With the rapid development of display technology, the market shows growing demands for high resolution, high brightness, and low power consumption in terms of the performance of display panels. However, with increases in a resolution of the display panel, because an amount of sub-pixels on the display panel also increases in order to display in high resolution, a manufacturing cost is also increased accordingly. In order to reduce the manufacturing cost of the display panel, a sub-pixel rendering (SPR) method have come into being. A display apparatus generally uses different arrangements and designs of the sub-pixels to formulate a proper algorithm so that the resolution may be increased to a sub-pixel resolution when an image is displayed. Because a size of the sub-pixel is smaller than that of a pixel, a resolution that is visible by human eye (i.e., a visual resolution) may be increased. In addition, a display driver may write pixel data into the display panel to display image frames according to different magnifications, so as to improve a light transmittance of the display panel. However, since the manufacturing of OLED materials in an OLED display is highly related to the fabrication process, fabrication issues may be encountered as the resolution of the OLED display increases, even may become the bottleneck to achieve high-resolution image display. Hence, how to design an OLED display that is capable of overcoming the above problems and achieving high resolution is an important issue that needs to be solved. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is directed to sub-pixel arrangement structures of an organic light emitting diode (OLED) display, which is capable of overcoming fabrication limitations and enhancing the light transmittance and the aperture ratio, thereby providing a good display quality with extending lifetime of the OLED display. 
     The invention provides a sub-pixel arrangement structure of an OLED display, including a plurality of sub-pixels arranged in a first direction and a second direction to form a sub-pixel array. The first direction is inclined at a first angle relative to a reference direction, and the second direction is inclined at a second angle relative to the reference direction. Each four sub-pixels of the plurality of sub-pixels form a virtual quadrangle, the each four sub-pixels include two sub-pixels having a same color, and the two sub-pixels having the same color are arranged at adjacent vertexes of the virtual quadrangle in one of the first direction and the second direction. 
     In an embodiment of the invention, the virtual quadrangles include a first virtual quadrangle and a second virtual quadrangle adjacently arranged in the reference direction. A color arrangement of the sub-pixels of the first virtual quadrangle that rotates by 180 degrees is identical to a color arrangement of the sub-pixels of the second virtual quadrangle. 
     In an embodiment of the invention, the virtual quadrangles include a third virtual quadrangle adjacently arranged to the first virtual quadrangle in a third direction, and the third direction is perpendicular to the reference direction. The color arrangement of the sub-pixels of the first virtual quadrangle that rotates by 180 degrees is identical to a color arrangement of the sub-pixels of the third virtual quadrangle. 
     In an embodiment of the invention, the virtual quadrangles include a first virtual quadrangle and a second virtual quadrangle adjacently arranged in the reference direction. A color arrangement of the sub-pixels of the first virtual quadrangle that is mirrored with respect to the one of the first direction and the second direction is identical to a color arrangement of the sub-pixels of the second virtual quadrangle. 
     In an embodiment of the invention, the virtual quadrangles include a third virtual quadrangle adjacently arranged to the first virtual quadrangle in a third direction, and the third direction is perpendicular to the reference direction. The color arrangement of the sub-pixels of the first virtual quadrangle that is mirrored with respect to the one of the first direction and the second direction is identical to a color arrangement of the sub-pixels of the third virtual quadrangle. 
     In an embodiment of the invention, the virtual quadrangles include a first virtual quadrangle, a second virtual quadrangle and a third virtual quadrangle adjacently and sequentially arranged in a third direction, and the third direction is perpendicular to the reference direction. Two sub-pixels of the first virtual quadrangle have a same first color, two sub-pixels of the second virtual quadrangle have a same second color, and two sub-pixels of the third virtual quadrangle have a same third color. The first color, the second color, and the third color are distinct from one another. 
     In an embodiment of the invention, a summation of the first angle and the second angle is larger than or substantially equal to 90 degrees. 
     In an embodiment of the invention, the OLED display includes scan lines, and the scan lines are arranged in the reference direction. 
     In an embodiment of the invention, the plurality of sub-pixels have a same size. 
     In an embodiment of the invention, shapes of the plurality of sub-pixels are square or diamond. 
     In an embodiment of the invention, the each four sub-pixels include red, green and blue sub-pixels, and the two sub-pixels having the same color are the red, the green or the blue sub-pixels. 
     The invention provides a sub-pixel arrangement structure of an OLED display, including a plurality of sub-pixels arranged in a first direction and a second direction to form a sub-pixel array. The first direction is inclined at a first angle relative to a reference direction, and the second direction is inclined at a second angle relative to the reference direction. The plurality of sub-pixels include a sub-pixel group having six sub-pixels. The six sub-pixels form a virtual quadrangle and include at least two sub-pixels having a same color, and the at least two sub-pixels having the same color are arranged at one vertex of the virtual quadrangle. 
     In an embodiment of the invention, the at least two sub-pixels include two first sub-pixels and two second sub-pixels. The two first sub-pixels are arranged at the one vertex of the virtual quadrangle and have a same first color, and the two second sub-pixels are arranged at another vertex of the virtual quadrangle and have a same second color. 
     In an embodiment of the invention, the six sub-pixels further include two third sub-pixels have a same third color, and the two third sub-pixels are separately arranged at other vertexes of the virtual quadrangle. 
     In an embodiment of the invention, the first color is selected from one of red, green and blue, the second color is selected from another one of red, green and blue, and the third color is selected from yet another one of red, green and blue. 
     In an embodiment of the invention, a summation of the first angle and the second angle is larger than or substantially equal to 90 degrees. 
     In an embodiment of the invention, the OLED display includes scan lines, and the scan lines are arranged in the reference direction. 
     In an embodiment of the invention, the at least two sub-pixels of the six sub-pixels have a same size smaller than sizes of rest sub-pixels of the six sub-pixels. 
     In an embodiment of the invention, shapes of the at least two sub-pixels of the six sub-pixels are rectangle or parallelogram, and shapes of rest sub-pixels of the six sub-pixels are square or diamond. 
     In an embodiment of the invention, the at least two sub-pixels are driven by a single driver or by two separate drivers. 
     Based on the above, the sub-pixel arrangement structure of the OLED display disclosed by the embodiments of the invention adaptively arranges sub-pixels of same color adjacent to effectively enlarge the emission area. Accordingly, both fabrication limitations and display quality, such as light transmittance and aperture ratio, may be taken into account. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
         FIG. 1  is a schematic diagram illustrating a display apparatus according to an embodiment of the invention. 
         FIG. 2  is a schematic diagram illustrating a pixel array and pixel data thereof according to an embodiment of the invention. 
         FIG. 3  is a schematic diagram illustrating a top view of a sub-pixel arrangement structure corresponding to the pixel array and the pixel data in the embodiment of  FIG. 2 . 
         FIG. 4  is a schematic diagram illustrating a top view of a display panel according to the sub-pixel arrangement structure in the embodiment of  FIG. 3 . 
         FIG. 5A to 5J  are schematic diagrams illustrating pixel types according to an embodiment of the invention. 
         FIG. 6  is a schematic diagram illustrating a top view of a display panel according to the sub-pixel arrangement structure in the embodiment of  FIG. 3 . 
         FIG. 7  is a schematic diagram illustrating a top view of a display panel according to a sub-pixel arrangement structure in an embodiment of the invention. 
         FIG. 8  and  FIG. 9  are schematic diagrams respectively illustrating a top view of a sub-pixel arrangement structure and a pixel array corresponding to the pixel data in the embodiment of  FIG. 2   
         FIG. 10  is a schematic diagram illustrating a top view of a sub-pixel arrangement structure corresponding to a pixel array and pixel data according to an embodiment of the invention. 
         FIG. 11A  is a schematic diagram illustrating a top view of a display panel according to the sub-pixel arrangement structure in the embodiment of  FIG. 10 . 
         FIG. 11B  is a schematic diagram illustrating a top view of parts of the sub-pixels on the display panel in the embodiment of  FIG. 11A . 
         FIG. 12  is a schematic diagram illustrating a top view of a sub-pixel arrangement structure corresponding to a pixel array and pixel data according to an embodiment of the invention. 
         FIG. 13A  is a schematic diagram illustrating a top view of a display panel according to the sub-pixel arrangement structure in the embodiment of  FIG. 12 . 
         FIG. 13B  is a schematic diagram illustrating a top view of parts of the sub-pixels on the display panel in the embodiment of  FIG. 13A . 
         FIG. 14  and  FIG. 15  are schematic diagrams respectively illustrating a top view of a sub-pixel arrangement structure corresponding to a pixel array according to an embodiment of the invention. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. 
       FIG. 1  is a schematic diagram illustrating a display apparatus according to an embodiment of the invention. Referring to  FIG. 1 , a display apparatus  100  in the present embodiment may be an OLED display, including a display driver  110  and a display panel  120 . The display driver  110  is coupled to the display panel  120 . The display driver  110  drives the display panel  120  to display image by using sub-pixel rendering (SPR) technology. In this embodiment, the display panel  120  includes a pixel array (not illustrated in  FIG. 1 ). The pixel array includes a plurality of color pixels, which are used for producing different colors, such as red, green and blue. The display driver  110  may drive, for example, two different color pixels for performing color mixing to display image frames. For convenience, red sub-pixels, green sub-pixels and blue sub-pixels are used for indicating the color pixels of red, green and blue respectively in the following description. 
     Specifically, each of the color pixels is generally defined by a region enclosed by two adjacent scan lines and two adjacent data lines. Besides, each of the color pixels includes a scan line and a data line, which are electrically connected with one OLED thin film. The OLED thin film may be used for producing colors of light, which may be patterned consistent with the design of a fine metal mask. In other words, a pattern of the OLED thin films on the display panel  120  may be affected by fabrication process. Additionally, Shapes of the OLED thin films may be different from shapes of the defined color pixels, and thereby the arrangement of the OLED thin films may have different arranging rules. Therefore, the embodiments of the invention may overcome the fabrication limitations by adjusting the configuration of the OLED thin films. Further, good display quality may be achieved. 
     It should be noted that, since the OLED thin films substantially correspond to the color pixels respectively, a “sub-pixel” is used for indicating the OLED thin film on the display panel  120 , and thereby a “sub-pixel arrangement structure” is used for indicating the configuration of the OLED thin films on the display panel  120  in the following description. 
       FIG. 2  is a schematic diagram illustrating a pixel array and pixel data thereof according to an embodiment of the invention.  FIG. 3  is a schematic diagram illustrating a top view of a sub-pixel arrangement structure corresponding to the pixel array and the pixel data in the embodiment of  FIG. 2 . Referring to  FIG. 1  to  FIG. 3 , in this embodiment, the display driver  110 , for example, drives the display panel  120  to display image by writing pixel data  200  into a pixel array  300 . The pixel array  300  in this embodiment may be part or all of pixel array on the display panel  120 . In addition, a pixel group  310  is arranged repeatedly to form the pixel array  300 . In the embodiment of  FIG. 2 , a 4×2 array of pixel data is illustrated for the pixel data  200 , which is written into the pixel array  300  with the same width as the pixel data  200 . However, it should be noted that the invention is not intended to limit the dimension of the pixel data  200  and width of the pixel array  300 , which may be adjusted according to the design requirements. Besides, the pixel data  200  includes red components R, green components G and blue components B, and the pixel array  300  includes color pixels, including red sub-pixels R, green sub-pixels G and blue sub-pixels B, as illustrated in  FIG. 2   
     In the present embodiment, the display driver  110  may write pixel data  210  with dimensions of 2×2 into the pixel group  310  by performing a 3/2 X data mapping (i.e. mapping three data into two sub-pixels). In detail, the pixel group  310  may be a rectangle-shaped array, which includes two rows of color pixels in an X direction and four columns of color pixels in a Y direction. Besides, scan lines of the display panel  120  may be arranged in the Y direction, and data lines of the display panel  120  may be arranged in the X direction. However, it should be noted that the invention is not limited thereto. The arrangement of the scan lines and the data lines of the display panel  120  may be adjusted according to the design requirements. 
     Referring to a sub-pixel arrangement structure  320  in the embodiment of  FIG. 3 , the shapes of each of the sub-pixels are square, while the shapes of the color pixels in the pixel group  310  are rectangle. Besides, in the sub-pixel arrangement structure  320 , the sub-pixels may be arranged in a D1 direction and a D2 direction, while the color pixels in the pixel group  310  may be arranged in the X direction and in the Y direction, where the D1 direction is inclined at a first angle A 1  relative to a reference direction (i.e. the Y direction), and the D2 direction is inclined at a second angle A 2  relative to the reference direction (i.e. the Y direction). Here, the first angle A 1  and the second angle A 2  may be both 45 degree. 
     Specifically, in the sub-pixel arrangement structure  320 , a first sequence along an arrangement path D 3  includes the red sub-pixel R, the green sub-pixel G, the green sub-pixel G and the blue sub-pixel B, and a second sequence along an arrangement path D 4  includes the green sub-pixel G, the blue sub-pixel B, the red sub-pixel R and the green sub-pixel G. Herein, the arrangement path D 3  and D 4  are paths composed of the D1 direction and the D2 direction. 
     It should be noted that the first sequence is similar to the arranging order of color pixels in the upper row of the pixel group  310  in the X direction, and the second sequence is similar to the arranging order of color pixels in the lower row of the pixel group  310  in the X direction. 
     Additionally, in the sub-pixel arrangement structure  320 , each four sub-pixels may include two sub-pixels having a same color, and the two sub-pixels having the same color may be arranged at adjacent vertexes of the virtual quadrangle in one of the D1 direction and the D2 direction. 
     The aforementioned virtual quadrangle may be illustrated clearly with reference to  FIG. 4 .  FIG. 4  is a schematic diagram illustrating a top view of a display panel according to the sub-pixel arrangement structure in the embodiment of  FIG. 3 . Referring to  FIG. 4 , a plurality of red, green and blue sub-pixels are arranged in the D1 direction and the D2 direction to form a sub-pixel array on a display panel  400  according to the sub-pixel arrangement structure  320  in  FIG. 3 . In this arrangement, each four sub-pixels form a virtual quadrangle, such as virtual quadrangles  410 ,  420  and  430 . In detail, the virtual quadrangle  410  may be formed by two green sub-pixels G 1 , G 2 , one blue sub-pixel B 1  and one red sub-pixel R 1 . In addition, the green sub-pixels G 1 , G 2  are arranged at adjacent vertexes of the virtual quadrangle  410  in the D1 direction. 
     Moreover, in the case of another virtual quadrangle  420 , which is adjacently arranged to the virtual quadrangle  410  in the reference direction (i.e. the Y direction), the virtual quadrangle  420  may be formed by two green sub-pixels G 1 , G 3 , one blue sub-pixel B 2  and one red sub-pixel R 2 . It should be noted that a color arrangement of the sub-pixels of the virtual quadrangle  410  that rotates by 180 degrees is identical to a color arrangement of the sub-pixels of the virtual quadrangle  420 . 
     As for the virtual quadrangle  430 , which is adjacently arranged to the virtual quadrangle  410  in the X direction (which is perpendicular to the Y direction), the virtual quadrangle  430  may be formed by two green sub-pixels G 4 , G 2 , one blue sub-pixel B 3  and one red sub-pixel R 3 . It should be also noted that the color arrangement of the sub-pixels of the virtual quadrangle  410  that rotates by 180 degrees is identical to a color arrangement of the sub-pixels of the virtual quadrangle  430 . 
     In this embodiment in  FIG. 4 , a summation of the first angle A 1  and the second angle A 2  is substantially equal to 90 degrees, while in other embodiments of the invention, the summation may be larger than 90 degrees. 
     As such, by using the sub-pixel arrangement structure  320  to arrange the sub-pixels on the display panel  400 , each two green sub-pixels may be arranged adjacently, so as to effectively enlarge the emission area of the green sub-pixels. Therefore, fabrication limitations may be overcome. Also, light transmittance of the green light and its color appearance or saturation may be improved, and aperture ratio of the green sub-pixels may increase for extending lifetime of the OLED of the display panel  120 . Besides, larger layout area for the source wiring of sub-pixels may be also provided. 
     It is worth mentioning that two sub-pixels with different colors may be deemed as a pixel unit to be combined and arranged to form the sub-pixel arrangement structure  320  of the aforementioned embodiment. More specifically,  FIG. 5A  to  FIG. 5J  are schematic diagrams illustrating pixel types according to an embodiment of the invention. Referring to  FIG. 5A  and  FIG. 5F  at first, a pixel unit  510  includes a red sub-pixel R and a green sub-pixel G, and a pixel unit  520  includes a green sub-pixel G and a blue sub-pixel B, where the green sub-pixels G of the pixel unit  510  and the pixel unit  520  are arranged adjacently. 
     Then, referring to  FIG. 5A  to  FIG. 5E , once pixel data to be written into the pixel unit  510  includes colors of red and/or green, the display driver  110  may directly drive the red sub-pixel R and/or green sub-pixel G in the pixel unit  510 . On the other hand, if the pixel data to be written into the pixel unit  510  includes colors of blue, the display driver  110  may drive the blue sub-pixel B in the adjacent pixel unit  520 . Besides, for displaying the white color, the display driver  110  may drive the red sub-pixel R and green sub-pixel G in the pixel unit  510  with the blue sub-pixel B in the adjacent pixel unit  520  together for color mixing. 
     Referring to  FIG. 5F  to  FIG. 5J , similarly, once pixel data to be written into the pixel unit  520  includes colors of green and/or blue, the display driver  110  may directly drive the green sub-pixel G and/or blue sub-pixel B in the pixel unit  520 . On the other hand, if the pixel data to be written into the pixel unit  520  includes colors of red, the display driver  110  may drive the red sub-pixel R in the adjacent pixel unit  510 . Besides, for displaying the white color, the display driver  110  may drive the green sub-pixel G and blue sub-pixel B in the pixel unit  520  with the red sub-pixel R in the adjacent pixel unit  510  together for color mixing. 
     In the previous embodiments, the sub-pixels in the sub-pixel arrangement structure  320  may have a same size. In the embodiment of  FIG. 3  as an example, each of the sub-pixels in the sub-pixel arrangement structure  320  may have a side length of √{square root over (2)}/2 P and a diagonal length P, where the “P” is indicated a pixel pitch as a length unit. It should be noted that the said diagonal length may be the same as a side length of the color pixels in the pixel group  310  in the Y direction. In other embodiments, sizes of the sub-pixels in the sub-pixel arrangement structure  320  may be adjusted adaptively, thereby the sub-pixels with different colors may have different sizes. 
       FIG. 6  is a schematic diagram illustrating a top view of a display panel according to the sub-pixel arrangement structure in the embodiment of  FIG. 3 . Referring to  FIG. 6 , a sub-pixel arrangement structure  600  in this embodiment is similar with the sub-pixel arrangement structure  320 , where lengths of each sub-pixels in the sub-pixel arrangement structure  600  are adjusted. In detail, since the emission area of each of the green sub-pixels has already enlarged as described above, a side length in the D2 direction of each green sub-pixel may be reduced. Besides, a side length in the D2 direction of each of the sub-pixels of the rest colors, including red and blue sub-pixels, may increase correspondingly. As a result, in the embodiment of  FIG. 6 , a life time of the sub-pixels of rest colors may be extended, while a life time of the green sub-pixels would not be affected. 
     In one embodiment, parts of the red sub-pixels and parts of the blue sub-pixels may be reversed.  FIG. 7  is a schematic diagram illustrating a top view of a display panel according to a sub-pixel arrangement structure in an embodiment of the invention. This embodiment is similar to the aforementioned embodiment in  FIG. 4 . Therefore, details of the same or similar elements are not repeated hereinafter. 
     Referring to  FIG. 7 , each four sub-pixels form a virtual quadrangle, such as virtual quadrangles  710 ,  720  and  730 . In detail, the virtual quadrangle  710  may be formed by two green sub-pixels G 1 , G 2 , one blue sub-pixel B 1  and one red sub-pixel R 1 , where the blue sub-pixel B 1  and the red sub-pixel R 1  included in the virtual quadrangle  710  are arranged opposite to the blue sub-pixel B 1  and the red sub-pixel R 1  included in the virtual quadrangle  410  in  FIG. 4 . 
     Further, in the case of another virtual quadrangle  720 , which is adjacently arranged to the virtual quadrangle  710  in the reference direction (i.e. the Y direction), the virtual quadrangle  720  may be formed by two green sub-pixels G 1 , G 3 , one blue sub-pixel B 2  and one red sub-pixel R 2 . It is worth mentioning that a color arrangement of the sub-pixels of the virtual quadrangle  710  that is mirrored with respect to the D1 direction is identical to a color arrangement of the sub-pixels of the virtual quadrangle  720 . 
     Besides, in the case of a virtual quadrangle  730 , which is adjacently arranged to the virtual quadrangle  710  in the X direction (which is perpendicular to the Y direction), the virtual quadrangle  730  may be formed by two green sub-pixels G, one blue sub-pixel B and one red sub-pixel R. It should be also noted that the color arrangement of the sub-pixels of the virtual quadrangle  710  that is mirrored with respect to the D1 direction is identical to a color arrangement of the sub-pixels of the virtual quadrangle  730 . 
     In other embodiments, the color arrangement of the sub-pixels of the virtual quadrangle  710  that is mirrored with respect to the one of the D1 direction and the D2 direction is identical to a color arrangement of the sub-pixels of the virtual quadrangle  720 . In addition, the color arrangement of the sub-pixels of the virtual quadrangle  710  that is mirrored with respect to the one of the D1 direction and the D2 direction is identical to a color arrangement of the sub-pixels of the virtual quadrangle  730 . In other words, the invention is not intended to limit the mirrored directions for arranging two virtual quadrangles to a single direction. 
     The aforementioned embodiments are applied for the case of adjacent green sub-pixels. Next, embodiments of adjacent red sub-pixels and adjacent blue sub-pixels are illustrated in  FIG. 8  and  FIG. 9  respectively. 
       FIG. 8  is a schematic diagram illustrating a top view of a sub-pixel arrangement structure and a pixel array corresponding to the pixel data in the embodiment of  FIG. 2 . Referring to  FIG. 1 ,  FIG. 2  and  FIG. 8 , in this embodiment, the display driver  110 , for example, drives the display panel  120  to display image by writing pixel data  200  into a pixel array  800 . Specifically, the display driver  110  may write pixel data  210  with dimensions of 2×2 into the pixel group  810  by performing a 3/2 X data mapping. This embodiment is similar to the aforementioned embodiment. Therefore, details of the same or similar elements are not repeated hereinafter. 
     In the present embodiment, the sub-pixel arrangement structure  820  includes sub-pixels arranged in a D1 direction and a D2 direction according to the arrangement of the pixel group  810 . Specifically, in the sub-pixel arrangement structure  820 , a first sequence along an arrangement path D 3  includes the green sub-pixel G, the red sub-pixel R, the red sub-pixel R and the blue sub-pixel B, and a second sequence along an arrangement path D 4  includes the red sub-pixel R, the blue sub-pixel B, the green sub-pixel G and the red sub-pixel R. Herein, the arrangement path D 3  and D 4  are paths composed of the D1 direction and the D2 direction. 
     Similarly, the first sequence is similar to the arranging order of color pixels in the upper row of the pixel group  810  in the X direction, and the second sequence is similar to the arranging order of color pixels in the lower row of the pixel group  810  in the X direction. 
     Besides, it should be noted that in the embodiment of  FIG. 8 , each virtual quadrangle may include two red sub-pixels arranged at adjacent vertexes in the D1 direction, so as to enlarge the emission area of the red sub-pixels. 
       FIG. 9  is a schematic diagram illustrating a top view of a sub-pixel arrangement structure and a pixel array corresponding to the pixel data in the embodiment of  FIG. 2 . Referring to  FIG. 1 ,  FIG. 2  and  FIG. 9 , in this embodiment, the display driver  110 , for example, drives the display panel  120  to display image by writing pixel data  200  into a pixel array  900 . Specifically, the display driver  110  may write pixel data  210  with dimensions of 2×2 into the pixel group  910  by performing a 3/2 X data mapping. This embodiment is similar to the aforementioned embodiment. Therefore, details of the same or similar elements are not repeated hereinafter. 
     In the present embodiment, the sub-pixel arrangement structure  920  includes sub-pixels arranged in a D1 direction and a D2 direction according to the arrangement of the pixel group  910 . Specifically, in the sub-pixel arrangement structure  920 , a first sequence along an arrangement path D 3  includes the green sub-pixel G, the blue sub-pixel B, the blue sub-pixel B and the red sub-pixel R, and a second sequence along an arrangement path D 4  includes the blue sub-pixel B, the red sub-pixel R, the green sub-pixel G and the blue sub-pixel B. Herein, the arrangement path D 3  and D 4  are paths composed of the D1 direction and the D2 direction. 
     Similarly, the first sequence is similar to the arranging order of color pixels in the upper row of the pixel group  910  in the X direction, and the second sequence is similar to the arranging order of color pixels in the lower row of the pixel group  910  in the X direction. 
     Besides, it should be noted that in the embodiment of  FIG. 9 , each virtual quadrangle may include two blue sub-pixels arranged at adjacent vertexes in the D1 direction, so as to enlarge the emission area of the blue sub-pixels. 
     In the aforementioned embodiments, the sub-pixels of one color may be arranged adjacent to enlarge the emission area. Next, adjacent subpixels of more than one color may be described as follows.  FIG. 10  is a schematic diagram illustrating a top view of a sub-pixel arrangement structure corresponding to a pixel array and pixel data according to an embodiment of the invention. Referring to  FIG. 1  and  FIG. 10 , the display driver  110  may write pixel data  1010  with dimensions of 3×2 into the pixel group  1020  by performing a 3/2 X data mapping. In the present embodiment, the sub-pixel arrangement structure  1030  includes sub-pixels arranged in a D1 direction and a D2 direction according to the arrangement of the pixel group  1020 . This embodiment is similar to the aforementioned embodiment. Therefore, details of the same or similar elements are not repeated hereinafter. 
     Specifically, in the sub-pixel arrangement structure  1030 , a first sequence along an arrangement path D 5  includes the blue sub-pixel B, the red sub-pixel R, the green sub-pixel G, the red sub-pixel R, the red sub-pixel R and the green sub-pixel G, and a second sequence along an arrangement path D 6  includes the green sub-pixel G, the blue sub-pixel B, the red sub-pixel R, the green sub-pixel G, the blue sub-pixel B and the red sub-pixel R. Herein, the arrangement path D 5  and D 6  are paths composed of the D1 direction and the D2 direction. Similarly, the first sequence is similar to the arranging order of color pixels in the upper row of the pixel group  1020  in the X direction, and the second sequence is similar to the arranging order of color pixels in the lower row of the pixel group  1020  in the X direction. 
       FIG. 11A  is a schematic diagram illustrating a top view of a display panel according to the sub-pixel arrangement structure in the embodiment of  FIG. 10 . Referring to  FIG. 11A , a plurality of red, green and blue sub-pixels are arranged in the D1 direction and the D2 direction to form a sub-pixel array on a display panel  1100  according to the sub-pixel arrangement structure  1030  in  FIG. 10 . In this arrangement, each four sub-pixels form a virtual quadrangle, such as virtual quadrangles  1110 ,  1120  and  1130 , which are adjacently and sequentially arranged in the X direction, which is perpendicular to the reference direction (i.e. the Y direction). 
     It is worth mentioning that, in the present embodiment, two sub-pixels of the virtual quadrangle  1110  have a same first color, two sub-pixels of the virtual quadrangle  1120  have a same second color, and two sub-pixels of the virtual quadrangle  1130  have a same third color, where the first color, the second color, and the third color are distinct from one another. 
     In the embodiment of  FIG. 11A  as an example, the virtual quadrangle  1110  may includes two red sub-pixels, the virtual quadrangle  1120  may includes two blue sub-pixels, and the virtual quadrangle  1130  may includes two green sub-pixels. More specifically, the virtual quadrangle  1110  may be formed by two red sub-pixels R 1 , R 2 , one blue sub-pixel B 1  and one green sub-pixel G 3 . The virtual quadrangle  1120  may be formed by two blue sub-pixels B 1 , B 2 , one green sub-pixel G 1  and one red sub-pixel R 3 . The virtual quadrangle  1130  may be formed by two green sub-pixels G 1 , G 2 , one red sub-pixel R 4  and one blue sub-pixel B 3 . 
       FIG. 11B  is a schematic diagram illustrating a top view of parts of the sub-pixels on the display panel in the embodiment of  FIG. 11A . Referring to  FIG. 11B , an arrangement  1100 A illustrates the distribution of the red sub-pixels R on the display panel  1100 , an arrangement  1100 B illustrates the distribution of the green sub-pixels G on the display panel  1100 , and an arrangement  1100 C illustrates the distribution of the blue sub-pixels B on the display panel  1100 . Thus, it may be seen that by using the sub-pixel arrangement structure  1030  to arrange sub-pixels on the display panel  1100 , each two sub-pixels with same color may be arranged adjacently, so as to enlarge the emission area of the sub-pixels of all colors. 
     It is worth mentioning that, in the embodiment of  FIG. 10 , each of the sub-pixels in the sub-pixel arrangement structure  320  may have a side length of √{square root over (2)}/2 P and a diagonal length P, which is similar to the aforementioned embodiment, based on the same ratio for data mapping. Thus, the summation of the first angle A 1  and the second angle A 2  in the present embodiment may be substantially equal to 90 degrees. 
     Some embodiments of the invention are also applicable for data mapping with different ratio.  FIG. 12  is a schematic diagram illustrating a top view of a sub-pixel arrangement structure corresponding to a pixel array and pixel data according to an embodiment of the invention. Referring to  FIG. 1  and  FIG. 12 , the display driver  110  may write pixel data  1210  with dimensions of 4×2 into the pixel group  1220  by performing a 2 X data mapping (i.e. mapping three data into one and half sub-pixels). In this embodiment, the sub-pixel arrangement structure  1230  includes sub-pixels arranged in a D1 direction and a D2 direction according to the arrangement of the pixel group  1220 . This embodiment is similar to the aforementioned embodiment. Therefore, details of the same or similar elements are not repeated hereinafter. 
     It should be noted that, in this embodiment, the shape of each sub-pixel in the sub-pixel arrangement structure  1230  may be diamond with a diagonal length of P and the other diagonal length of 4/3 P. In other words, the D1 direction and the D2 direction in the present embodiment are different from the aforementioned embodiments, where the summation of the first angle A 1  and the second angle A 2  in the present embodiment may be larger than 90 degrees. 
     In the sub-pixel arrangement structure  1230 , a first sequence along an arrangement path D 7  includes the blue sub-pixel B, the red sub-pixel R, the green sub-pixel G, the red sub-pixel R, the red sub-pixel R and the green sub-pixel G, and a second sequence along an arrangement path D 8  includes the green sub-pixel G, the blue sub-pixel B, the red sub-pixel R, the green sub-pixel G, the blue sub-pixel B and the red sub-pixel R. Herein, the arrangement path D 7  and D 8  are paths composed of the D1 direction and the D2 direction. Similarly, the first sequence is similar to the arranging order of color pixels in the upper row of the pixel group  1220  in the X direction, and the second sequence is similar to the arranging order of color pixels in the lower row of the pixel group  1220  in the X direction. 
       FIG. 13A  is a schematic diagram illustrating a top view of a display panel according to the sub-pixel arrangement structure in the embodiment of  FIG. 12 . Referring to  FIG. 13A , a plurality of red, green and blue sub-pixels are arranged in the D1 direction and the D2 direction to foam a sub-pixel array on a display panel  1300  according to the sub-pixel arrangement structure  1230  in  FIG. 12 . In this arrangement, each four sub-pixels form a virtual quadrangle, such as virtual quadrangles  1310 ,  1320  and  1330 , which are adjacently and sequentially arranged in the X direction, which is perpendicular to the reference direction (i.e. the Y direction). 
     Since the sub-pixel arrangement structure  1230  in the embodiment of  FIG. 12  is similar with the sub-pixel arrangement structure  1030  in the embodiment of  FIG. 10 , thereby the virtual quadrangles  1310 ,  1320  and  1330  may also similar with the virtual quadrangles  1110 ,  1120  and  1130  respectively. In other words, the virtual quadrangle  1310  may include two red sub-pixels, the virtual quadrangle  1320  may include two blue sub-pixels, and the virtual quadrangle  1330  may include two green sub-pixels. 
       FIG. 13B  is a schematic diagram illustrating a top view of parts of the sub-pixels on the display panel in the embodiment of  FIG. 13A . Referring to  FIG. 13B , an arrangement  1300 A illustrates the distribution of the red sub-pixels R on the display panel  1300 , an arrangement  1300 B illustrates the distribution of the green sub-pixels G on the display panel  1300 , and an arrangement  1300 C illustrates the distribution of the blue sub-pixels B on the display panel  1300 . Thus, it may be seen that by using the sub-pixel arrangement structure  1230  to arrange the sub-pixels on the display panel  1300 , each two sub-pixels with same color may be arranged adjacently. Further, the area of each of the sub-pixels in the sub-pixel arrangement structure  1230  may be 2/3 P 2 , which is larger than the area (i.e. 1/2 P 2 ) of each of the sub-pixels in the sub-pixel arrangement structure  1230 . Thereby, the emission area of the sub-pixels of all colors may be enlarged more effectively. 
     In some embodiments, columns of extra sub-pixels may be add into the sub-pixel arrangement structure for providing color mixing with adjacent columns to improve display quality.  FIG. 14  and  FIG. 15  are schematic diagrams respectively illustrating a top view of a sub-pixel arrangement structure corresponding to a pixel array according to an embodiment of the invention. 
     Referring to  FIG. 1  and  FIG. 14  at first, in this embodiment, a pixel array  1410  may be part or all of pixel array on the display panel  120 , and a pixel group  1412  is arranged repeatedly to form the pixel array  1410 . The pixel group  1412  may include a column of extra sub-pixels R 2  and B 4 , which are respectively adjacent with sub-pixels R 3  and B 5  of another pixel group next to the pixel group  1412 . As for a sub-pixel arrangement structure  1420 , the sub-pixels in the sub-pixel arrangement structure  1420  may be arranged in the D1 direction and the D2 direction according to the arrangement of the pixel group  1412 , where the D1 direction may be inclined at a first angle A 1  relative to a reference direction (i.e. the Y direction), the D2 direction may be inclined at a second angle A 2  relative to a reference direction (i.e. the Y direction), and a summation of the first angle A 1  and the second angle A 2  may be larger than or substantially equal to 90 degrees. Besides, the scan lines the OLED display  100  may be arranged in the reference direction (i.e. the Y direction). 
     Specifically, In the sub-pixel arrangement structure  1420 , a first sequence along an arrangement path D 9  includes the red sub-pixel R 1 , the green sub-pixel G 1 , the blue sub-pixel B 1 , the green sub-pixel G 2 , the red sub-pixel R 2 , the red sub-pixel R 3 , the green sub-pixel G 3 , the blue sub-pixel B 2 , the green sub-pixel G 4  and the red sub-pixel R 4 , and a second sequence along an arrangement path D 10  includes the blue sub-pixel B 3 , the green sub-pixel G 5 , the red sub-pixel R 5 , the green sub-pixel G 6 , the blue sub-pixel B 4 , the blue sub-pixel B 5 , the green sub-pixel G 7 , the red sub-pixel R 6 , the green sub-pixel G 8  and the blue sub-pixel B 6 . Herein, the arrangement path D 9  and D 10  are paths composed of the D1 direction and the D2 direction. Similarly, the first sequence is similar to the arranging order of color pixels in the upper row of the pixel group  1410  in the X direction, and the second sequence is similar to the arranging order of color pixels in the lower row of the pixel group  1410  in the X direction. 
     In the present embodiment, the plurality of sub-pixels may include a sub-pixel group having six sub-pixels, where the six sub-pixels form a virtual quadrangle and include at least two sub-pixels having a same color. The at least two sub-pixels having the same color are arranged at one vertex of the virtual quadrangle. In addition, the at least two sub-pixels of the six sub-pixels have a same size smaller than sizes of rest sub-pixels of the six sub-pixels. Further, shapes of the at least two sub-pixels of the six sub-pixels are rectangle or parallelogram, and shapes of rest sub-pixels of the six sub-pixels are square or diamond. 
     More specifically, a virtual quadrangle  1422  in this embodiment may be formed by six sub-pixels the red sub-pixels R 2 , R 3 , the green sub-pixel G 3 , the blue sub-pixels B 4 , B 5  and the green sub-pixel G 2 . The sub-pixels R 2  and R 3 , which have the same color of red, are arranged at the upper vertex of the virtual quadrangle  1422 , and the sub-pixels B 4  and B 5 , which have the same color of blue, are arranged at the lower vertex of the virtual quadrangle  1422 . Besides, the two sub-pixels G 2  and G 3 , which have the same color of green, are separately arranged at other vertexes (for example, left vertex and right vertex) of the virtual quadrangle  1422 . 
     It is worth mentioning that the red sub-pixels R 2  and R 3  having a same size, and the blue sub-pixels B 4  and B 5  are also having the same size, where the said size is smaller than sizes of rest sub-pixels (i.e. the green sub-pixels G 2  and G 3 ) of the six sub-pixels of the virtual quadrangle  1422 . Besides, shapes of the red sub-pixels R 2 , R 3  and the blue sub-pixels B 4  and B 5  are rectangle, and shapes of rest sub-pixels of the six sub-pixels, that is, the green sub-pixels G 2  and G 3 , are square. In other embodiments, shapes of the red sub-pixels R 2 , R 3  and the blue sub-pixels B 4  and B 5  may be rectangle or parallelogram, and shapes of rest sub-pixels of the six sub-pixels may be square or diamond. The invention in not intended to limit the shapes of the sub-pixels. 
     It should be also noted that the at least two sub-pixels may be driven by a single driver or by two separate drivers. In one embodiment, the display driver  110  is configured to drive all the sub-pixels of the sub-pixel arrangement structure  1420  (i.e. all the color pixels of the pixel group  1410 ). In other embodiments, the display driver  110  may include a first driver and a second driver. The first driver may be used for driving the left part of the pixel array  1410  (i.e. the pixel group  1412 ), which corresponds to the left part of the sub-pixel arrangement structure  1420 , and the second driver may be used for driving the right part of the pixel array  1410 , which corresponds to the right part of the sub-pixel arrangement structure  1420 . Accordingly, the sub-pixels R 2  and R 3  in this embodiment may be driven by the first driver and the second driver separately, and a break point may be formed between the sub-pixels R 2  and R 3 . Similarly, the sub-pixels B 4  and B 5  may be also driven by the first driver and the second driver separately, and another break point may be formed between the sub-pixels B 4  and B 5 . Hence, needs of data transferring between each of the driving circuits may be avoided, thereby effectively simplifying the design of the display driver  110 . 
       FIG. 15  illustrates another sub-pixel arrangement structure  1520  corresponding to a pixel array  1510  with extra sub-pixels included in a pixel group  1512 . Similarly, the sub-pixels in the sub-pixel arrangement structure  1520  may be arranged in the D1 direction and the D2 direction according to the arrangement of the pixel group  1512 . 
     Specifically, In the sub-pixel arrangement structure  1520 , a first sequence along an arrangement path D 11  includes the red sub-pixel R, the green sub-pixel G, the blue sub-pixel B, the green sub-pixel G, the red sub-pixel R, the green sub-pixel G, the blue sub-pixel B, the blue sub-pixel B, the green sub-pixel G, the red sub-pixel R, the green sub-pixel G, the blue sub-pixel B, the green sub-pixel G and the red sub-pixel R, and a second sequence along an arrangement path D 12  includes the blue sub-pixel B, the green sub-pixel G, the red sub-pixel R, the green sub-pixel G, the blue sub-pixel B, the green sub-pixel G, the red sub-pixel R the red sub-pixel R, the green sub-pixel G, the blue sub-pixel B, the green sub-pixel G, the red sub-pixel R, the green sub-pixel G and the blue sub-pixel B. Herein, the arrangement path D 11  and D 12  are paths composed of the D1 direction and the D2 direction. Similarly, the first sequence is similar to the arranging order of color pixels in the upper row of the pixel group  1510  in the X direction, and the second sequence is similar to the arranging order of color pixels in the lower row of the pixel group  1510  in the X direction. 
     Particularly, a virtual quadrangle  1522  may be formed by six sub-pixels, including two blue sub-pixels arranged at the upper vertex of the virtual quadrangle  1522 , two red sub-pixels arranged at the lower vertex of the virtual quadrangle  1522 , and two green sub-pixels separately arranged at other vertexes of the virtual quadrangle  1522 . Similarly, for the case that the display driver  110  may include two separate drivers, the two blue sub-pixels arranged at the upper vertex of the virtual quadrangle  1522  may be driven by two drivers separately, and the two red sub-pixels arranged at the lower vertex of the virtual quadrangle  1522  may be driven by two drivers separately. This embodiment is similar to the aforementioned embodiment. Therefore, details of the same or similar elements are not repeated hereinafter. 
     To conclude the above, the sub-pixel arrangement structures of the OLED display according to the embodiments of the invention adaptively configure the sub-pixels of the same color to be adjacent, with the shapes of the sub-pixels being square or diamond, so as to effectively enlarge the emission area. Embodiments of arranging sub-pixels of one color adjacent and embodiments of arranging sub-pixels of all colors adjacent separately are both provided. In addition, the embodiments of the invention are also capable of applying for the design with extra sub-pixels for color mixing. Accordingly, fabrication limitations may be overcome, the light transmittance and the aperture ratio may be enhanced, and thereby a good display quality with extending lifetime of the OLED display may be achieved. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.