Patent ID: 7187005

Claim:
A flat panel display having a plurality of sub-pixels, each sub-pixel comprising: a light emitting device; a switching thin film transistor including a semiconductor active layer having at least a channel area for transferring a data signal to the light emitting device; and only one driving thin film transistor including a semiconductor active layer having at least a channel area for driving the light emitting device so that a predetermined current flows through the light emitting device according to the data signal, wherein with respect to a direction of any grain boundary, the channel area of the switching transistor is situated along a first direction and the channel area of the driving transistor is situated along a second direction, wherein a direction of current flow with respect to the grain boundary at the channel area of the switching thin film transistor is different from a direction of current flow with respect to the grain boundary at the channel area of the switching thin film transistor, and wherein the direction of current flow in the channel area of the switching thin film transistor and the direction of current flow in the channel area of the driving thin film transistor are formed so that a current mobility in the channel area of the switching thin film transistor is larger than a current mobility in the channel area of the driving thin film transistor.