Support For Both Touch Sensing And Fingerprint Scan With In-Cell Capacitive Lcd

The need for touch based authentication is growing rapidly in smartphones and tablets. Historically, fingerprint has served at its fullest capacity in establishing the uniqueness of an individual's identity. In this paper we present a novel design of capacitive in-cell TFT-LCDs that supports both fingerprint scan and touch sensing by extending the in-cell capacitive sensing scheme. We discuss a novel readout circuit design that drives the capacitive sensors for touch interactions in low resolution and for fingerprint scan at higher resolution. Furthermore, we propose to enhance the low resolution fingerprint data with image super resolution. Evaluation results show that with super resolution, the proposed touch-fingerprint in-cell TFT-LCD design can support fingerprint verification with sensor pitch of 0.15mm.