Patent ID: 7863602

Claim:
An organic light emitting diode display, comprising: a substrate; a first signal line formed on the substrate; a second signal line intersecting the first signal line; a first thin film transistor connected to the first and second signal lines; a second thin film transistor connected to the first thin film transistor; a first electrode connected to the second thin film transistor; a second electrode provided at least partially opposite to the first electrode; and a light emitting member formed between the first electrode and the second electrode, wherein the first thin film transistor comprises a first lower semiconductor layer and a first upper semiconductor layer having different crystallinity from that of the first lower semiconductor layer, and the second thin film transistor comprises a second lower semiconductor layer and a second upper semiconductor layer having different crystallinity from that of the second lower semiconductor layer, wherein each of the first lower semiconductor layer and the second lower semiconductor layer comprises an amorphous semiconductor, and each of the first upper semiconductor layer and the second upper semiconductor layer comprises a microcrystalline or polycrystalline semiconductor.