Pixel Circuit With P-Type Low-Temperature Polycrystalline Silicon Thin-Film Transistor for Micro Light-Emitting Diode Displays Using Pulse Width Modulation

Herein, we present a novel low-temperature polycrystalline silicon (LTPS) thin-film transistor (TFT) pixel circuit for a micro light-emitting diode (mu LED) display based on puke width modulation (PWM). By adopting PWM, we could achieve 10-bit gray levels of mu LED without wavelength shift, which is a challenge in the realization of mu LEDs. Furthermore, the proposed circuit compensated for the variation in threshold voltage (V-TH) without an external sensing system. We simulated the error rate of the mu LED emission time of the proposed pixel circuit depending on the V-TH change. We measured the wavelength shift of the mu LED using the fabricated circuit. This shift in PWM was smaller than that in pulse amplitude modulation (PAM). Consequently, the proposed pixel circuit could overcome screen distortions caused by color shifts of mu LED displays using PWM techniques.

Automated summary

The study introduces a novel low-temperature polycrystalline silicon thin-film transistor pixel circuit for PWM-based mu LED displays. It achieves 10-bit gray levels without wavelength shift and compensates for V-TH variations, offering a solution to color distortions in mu LED displays.