A flat panel display which can adjust a white balance to a proper level according to the difference among the crystal grains of driving TFT active layers without changing the sizes of the driving TFT active layers. The flat panel display also can obtain an appropriate luminance by supplying an optimal amount of current to each sub-pixel. The flat panel display has a plurality of pixels. Each of the pixels includes a plurality of sub-pixels and each sub-pixel has a self-luminescent element and a driving thin film transistor. Each of the driving thin film transistors has a semiconductor active layer having a channel region is connected to the self-luminescent element of the corresponding sub-pixel in order to supply current to each of the self-luminescent elements. At least the channel regions of the semiconductor active layers have crystal grains of different sizes or shapes for different sub-pixels.