-Two simple pixel circuits are proposed for high resolution and high image quality organic light-emitting diode-on-silicon microdisplays. The proposed pixel circuits achieve high resolution due to simple pixel structure comprising three n-type MOSFETs and one storage capacitor, which are integrated into a unit subpixel area of 3 × 9 μm 2 using a 90 nm CMOS process. The proposed pixel circuits improve image quality by compensating for the threshold voltage variation of the driving transistors and extending the data voltage range. To verify the performance of the proposed pixel circuits, the emission currents of 24 pixel circuits are measured. The measured emission current deviation error of the proposed pixel circuits A and B ranges from À2.59% to +2.78%, and from À1.86% to +1.84%, respectively, which are improved from the emission current deviation error of the conventional current-source type pixel circuit when the threshold voltage variation is not compensated for, which ranges from À14.87% to +14.67%. In addition, the data voltage ranges of the proposed pixel circuits A and B are 1.193 V and 1.792 V, respectively, which are 2.38 and 3.57 times wider than the data voltage range of the conventional current-source type pixel circuit of 0.501 V.

In this paper, a simple pixel circuit is proposed for the high resolution organic light emitting diode-on-silicon (OLEDoS) microdisplay. The proposed pixel circuit achieves a wide input data voltage range using the body effect and suppresses the emission current deviation due to the threshold voltage variation of the driving transistor using the capacitive coupling effect. The proposed pixel circuit which consists of three n-type MOSFETs and one storage capacitor occupies an area of 3 μm × 9 μm. The simulated results show that the proposed pixel circuit achieves maximum input data voltage ranges of 1.37 V, 1.51 V, and 1.34 V for red, green, and blue OLED, respectively, from 1-gray to 255-gray level, and the emission current error ranges from −2.85% to +2.96% under the threshold voltage variation of ±5 mV.