Engineering considerations for the application of threshold voltage one-time detection (OTD) method in LTPO AMOLED displays

Abstract

LTPO (LTPS&Oxide) AMOLED display can work in a wide refresh rate range such as 1–120 Hz in the advantage of the low off current for oxide TFTs. Threshold voltage one-time detection (OTD) architecture is a potential low-power technology including the connotations of nonvolatile memory and in-memory computing, which can be applied in the LTPO AMOLED to greatly decrease the dynamic power consumption, especially at the high refresh rate. An LTPO pixel circuit driven by the OTD method is presented, in which there exists a data refresh frame without threshold voltage compensation compared with the traditional LTPO pixel circuit. However, for the OTD LTPO pixel circuit, the pixel area is a little larger, and feed through effect induced by capacitor coupling could be more serious due to the two series-connected storage capacitors. The flicker induced by the hysteresis of the driving TFT may be more severe since the threshold voltage of driving TFT is only compensated once per Nc frame.