Power saving through state retention in IGZO-TFT AMOLED displays for wearable applications

© (2017) by SID-the Society for Information Display. All rights reserved. We present a qHD (960×540 with 3 sub-pixels) top-emitting 'AMOLED display with 340ppi resolution using a self-aligned (SA) IGZO TFT backplane on polyimidefoil with humidity barrier. The back plane process flow is based on a 7 layer photolithography process with a CD=4um. We implement a 2TIC pixel engine and use commercial source driver IC made for LTPS. By using IGZO TFT and leveraging the extremely low off-current, we can switch-offthe power to the source and gate driver while maintaining the image un-changed for several minutes We demonstrate that, depending on the image content, low-refresh operation yields reduction in power consumption of up to 50% compared to normal (continuous) operation. We show that with further increase in resolution, the power saving through state retention will be even more significant.