A 4T1C Pixel Circuit with Threshold Voltage Compensation for Organic Light-Emitting Diode on Silicon Microdisplays

In this paper, a pixel circuit consists of four MOSFETs and one capacitor is proposed for Organic Light-Emitting Diode on Silicon (OLEDoS) microdisplays. The proposed pixel circuit enhances luminance uniformity by compensating for the threshold voltage variation of the driving transistors by the capacitive coupling effect. Even with a threshold voltage variation of ±20 mV, the HSPICE simulation results reveal that the driving current offset stays between −0.89 and 0.70 LSB, which is more than seven times smaller than that of the conventional 2T1C pixel circuit. Additionally, a two-stage DAC driving scheme has been utilized to achieve 256 gray levels, aiming to reduce the accuracy requirements for the DAC circuit. The proposed pixel circuit demonstrates significant potential in high-performance OLEDoS microdisplay applications.