An organic light emitting device (OLED) is formed by assembling a first substrate and a second substrate. The second substrate includes several sub-pixels. The first substrate includes several transistors electrically connected to each other and, for each subpixel, a first connecting electrode electrically connected to one of the transistors. Each subpixel includes a light-emitting region and a non light-emitting region. A second connecting electrode is formed in the non light-emitting region and electrically connected to the respective first connecting electrode.