A pixel array includes a plurality of pixels. Each pixel has a first sub-pixel, a second sub-pixel, and a pair of third sub-pixels. The first sub-pixel of each pixel and the first sub-pixels of three adjacent pixels are arranged in a two by two array, the second sub-pixel of each pixel and the second sub-pixels of three adjacent pixels are arranged in a two by two array, and one of each of the third sub-pixels of each pixel and one of the third sub-pixels of three adjacent pixels are arranged in a two by two array. A scan line is connected to a switch unit of each of the sub-pixels in a pixel.