Large Area Multi-Functional Ultrasound Sensor: Fingerprint, Touch Pressure, Passive Stylus

This paper reports the first demonstration of a large area (20×30mm ² ), multi-functional, highly integrated, thin ultrasound sensor under thick (> 1mm) mobile display comprised of organic light-emitting diode (OLED) and protecting cover glass (CG). The sensor, based on ultra-thin piezoelectric copolymer transducer array fully integrated with low-cosst thin film transistors (TFT) circuitry on glass substrate, enables the highperformance sensing of not only fingerprint features, but also finger touch pressure level and non-electro-magnetic stiff stylus position and tracking. The large area ultrasound sensor provides flexibility of finger touch location and therefore better user experience for fingerprint sensing. Meanwhile multi-finger authentication significantly improves reliability and security. Furthermore, the touch pressure sensing and passive stylus tracking enrich the user experience in the scenarios of, such as gaming, shopping, education, etc.