Micro Light-Emitting Diode Pixel Circuit Based on Indium–Gallium–Zinc Oxide Thin-Film Transistors Using Pulse Width Modulation

Herein, we proposed a micro light-emitting diode (μLED) pixel circuit based on indium–gallium–zinc oxide (IGZO) thin-film transistors (TFTs). Pulse-width modulation (PWM) was utilized to overcome the wavelength shift of theμLEDs. The proposed pixel circuit compensated for the threshold voltage (VTH)of the driving TFTs using a source-follower structure and the variation ofμLED forward voltage (Δ VLED). The proposedμLED pixel circuit successfully expressed 256 gray levels using PWM. In addition, the proposed circuit exhibited a normalized luminance error rate lower than 4.8% underVTHvariation (Δ VTH)of ±1.0 andΔ VLEDof ±0.4 V. Consequently, the proposedμLED pixel circuit based on IGZO TFTs successfully expressed gray levels using PWM and operated stably underΔ VTHandΔ VLED.