Multi-Modal Full-Area High-Resolution Human-Machine Interactive Surface with 3D Stacking of IGZO TFT Active-Matrix Capacitive and Optical Sensing Arrays

This work proposes a three-dimensional stacking architecture, incorporating an active-matrix optical sensor array and a touch one based on indium gallium zinc oxide (IGZO) thin-film transistor (TFT) backplane on glass substrate, for multi-modal human-machine interactive (HMI) surface. With a semi-transparent active pixel capacitive touch sensor array (−298 ppi) integrated on top of a high resolution $(\sim 500$ ppi) organic photodiode optical one, multi-modal functions of full-area capacitive/optical dual-mode fingerprint authentication, and touch/3D-remote interaction are realized in one compact system. Being fully compatible with the back-end-of-line process of the TFT backplane from the semiconductor display fab, this technology is scalable for large-area and large-volume manufacturing.