Low temperature polycrystalline silicon TFT fingerprint sensor with integrated comparator circuit

Abstract

We have developed a low-temperature polycrystalline silicon thin film transistor (LTPS-TFT) fingerprint sensor (FPS) based on a newly clarified detection principle and a unique driving scheme. We have also integrated a comparator circuit onto a glass substrate for the first time. The circuit recognizes ridges and valleys in a fingerprint. Using this system, we have succeeded in taking fine fingerprint images at 4 V operation. This fingerprint sensor is suitable for mobile applications that require thin devices that are low cost and low power.