Drain currents as functions of the gate voltages for the thin-film transistors (TFTs) showed that their output currents had slight differential variations in the saturation region just as the output currents of the etch stopper TFTs did. The maximum difference in the threshold voltages for the In-Ga-Zn-O (a-IGZO) TFTs was as small as approximately 0.57 V. The color gamut of organic light-emitting devices (OLEDs) embedded with TFTs with a coplanar structure satisfied the digital cinema initiatives of 99%. Furthermore. the image density of large-size OLEDs embedded with TFTs with a coplanar structure was significantly enhanced in comparison with that of OLEDs embedded with conventional TFTs. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement