Patent ID: 8502206

Claim:
An organic light emitting diode (OLED) display device, comprising: a plurality of scan lines, a plurality of data lines, and a plurality of pixels disposed in a region in which the scan lines cross the data lines, wherein each pixel of the plurality of pixels comprises: a switching transistor comprising a first gate electrode, a first semiconductor layer disposed over the first gate electrode, a first gate insulating layer interposed between the first gate electrode and the first semiconductor layer, a first source electrode and a first drain electrode; a driving transistor comprising a second semiconductor layer, a second gate electrode disposed over the second semiconductor layer, a second gate insulating layer interposed between the second gate electrode and the second semiconductor layer, a second source electrode and a second drain electrode, wherein the first gate insulating and the second gate insulating layer are separate layers; an organic light emitting diode electrically connected with the second source and second drain electrodes of the driving transistor; and a first etch stop layer disposed over and contacting at least a partial region of the first semiconductor layer, and a second etch stop layer disposed over and contacting at least a partial region of the second semiconductor layer.