DISPLAY DEVICE

A thin film transistor substrate includes a first thin film transistor disposed having a polycrystalline semiconductor layer, a first gate electrode on the polycrystalline semiconductor layer, a first source electrode and a first drain electrode; a first gate insulating layer between the polycrystalline semiconductor layer and the first gate electrode; a second thin film transistor disposed having an oxide semiconductor layer on the first gate electrode, a second gate electrode on the oxide semiconductor layer, a second source electrode and a second drain electrode; an intermediate insulating layer disposed on the first gate electrode and under the oxide semiconductor layer; and a second gate insulating layer on the intermediate insulating layer and under the first source electrode, the first drain electrode and the second gate electrode.