Biometric sensor and low-temperature thin film transistor integration technology for next-generation displays

Abstract

The degree of interaction between users and electronic devices has increased with the emergence of the Internet of Things (IoT). Therefore, security is also becoming increasingly important to protect personal information. In this study, thin-film biometric authentication technologies were developed for application to commercial mobile devices, and for user convenience. First, a mutual capacitive transparent fingerprint sensor (FPS) was developed that enabled multitouch functionality without ghost effects and improved ridge sensing through a newly designed reference electrode. In addition, an under-display fingerprint-vein multimodal sensor system using visible light was designed to further improve the recognition rate of the existing unimodal biometric sensing system. The multimodal sensor was fabricated using an organic photodiode (PM6:Y7), and an environmental study of oxide thin-film transistors (TFTs) was performed for driving stability. Finally, the monolithic integration method of dual-gated TFTs was developed for high-resolution micro-light-emitting diode (LED) displays, which can be applied to IoT displays.