A portable device comprising: an organic light emitting display panel having a pixel arrangement structure comprising a plurality of first sub-pixels, a plurality of second sub-pixels and a plurality of third sub-pixels for displaying an image; the pixel arrangement structure comprising a first pixel region and a second pixel region alternately arranged in the row direction and in the column direction to form the display panel; the first pixel region comprising one of the plurality of the first sub-pixels arranged at the lower right corner of said first pixel region and one of the plurality of the second sub-pixels arranged at the top left corner of said first pixel region, the first sub-pixel and the second sub-pixel being arranged along a first diagonal of said first pixel region; the second pixel region comprising another one of the plurality of the first sub-pixels arranged at the lower right corner of said second pixel region and one of the plurality of third sub-pixels arranged at the top left corner of said second pixel region, the first sub-pixel and the third sub-pixel being arranged along a first diagonal of said second pixel region; wherein the first sub-pixel has a rectangular shape and is arranged such that the longer edges are parallel to said first diagonal of said first pixel region in the first pixel region and such that the shorter edges are parallel to said first diagonal of the second pixel region in the second pixel region; wherein each of the second sub-pixel and the third sub-pixel has a square shape with two edges parallel to the first diagonal in the first pixel region and in the second pixel region, respectively; wherein the first sub-pixel is formed to have a smaller area than each of the second sub-pixel and the third sub-pixel; and wherein the first sub-pixel is a green sub-pixel, the second sub-pixel is a red sub-pixel and the third sub-pixel is a blue sub-pixel. an organic light emitting display panel having a pixel arrangement structure comprising a plurality of first sub-pixels, a plurality of second sub-pixels and a plurality of third sub-pixels for displaying an image; the pixel arrangement structure comprising a first pixel region and a second pixel region alternately arranged in the row direction and in the column direction to form the display panel; the first pixel region comprising one of the plurality of the first sub-pixels arranged at the lower right corner of said first pixel region and one of the plurality of the second sub-pixels arranged at the top left corner of said first pixel region, the first sub-pixel and the second sub-pixel being arranged along a first diagonal of said first pixel region; the second pixel region comprising another one of the plurality of the first sub-pixels arranged at the lower right corner of said second pixel region and one of the plurality of third sub-pixels arranged at the top left corner of said second pixel region, the first sub-pixel and the third sub-pixel being arranged along a first diagonal of said second pixel region; wherein the first sub-pixel has a rectangular shape and is arranged such that the longer edges are parallel to said first diagonal of said first pixel region in the first pixel region and such that the shorter edges are parallel to said first diagonal of the second pixel region in the second pixel region; wherein each of the second sub-pixel and the third sub-pixel has a square shape with two edges parallel to the first diagonal in the first pixel region and in the second pixel region, respectively; wherein the first sub-pixel is formed to have a smaller area than each of the second sub-pixel and the third sub-pixel; and wherein the first sub-pixel is a green sub-pixel, the second sub-pixel is a red sub-pixel and the third sub-pixel is a blue sub-pixel.