A Self-Refreshing Memory-in-Pixel Comprising Low Temperature Poly-Silicon and Oxide TFTs for 3-Bit Liquid Crystal Displays

In this letter, a self-refreshing multi-level memory-in-pixel (MIP) circuit for liquid crystal display (LCD) comprising low temperature poly-silicon and oxide (LTPO) thin film transistors (TFTs) is proposed. Since the proposed MIP circuit features self-refreshing without embedding frame memory, power consumption can be minimized when displaying a still image. Measurement results verify that the proposed circuit successfully enables a 3-bit grayscale. The LCD employing the proposed MIP circuit consumes only 1.22 % of power compared with a conventional LCD when displaying a still image. Thus, the proposed multi-level MIP circuit is expected to enable a low-power LCD featuring higher color depth with a simple structure.