A Low-Power Memory-in-Pixel Circuit for Liquid Crystal Displays Comprising Low-Temperature Poly-Silicon and Oxide Thin-Film Transistors

Abstract

In this paper, a new pixel structure using low-temperature polycrystalline silicon and oxide (LTPO) thin-film transistors (TFTs) for low-power liquid crystal displays (LCDs) is proposed. The extremely low off-state current of oxide semiconductor TFTs enables the proposed circuit to operate at a very low frame frequency of 1/60 Hz, so that the power consumption can be significantly reduced. In addition, the low-temperature polycrystalline silicon TFTs with high reliability directly drive pixels, which can achieve stable and flicker-free LCDs. The proposed circuit is fabricated using the LTPO TFT backplane and successfully verified by simulation and measurement results. The measurement results prove that the proposed circuit operates well without further programming for 60 s, and the power consumption in the panel (except backlight power) can be reduced to 0.02% of that of conventional LCD.