P‐5: New Capacitive Active‐Pixel Sensor Based on LTPS‐TFT Backplane Technology for Fingerprint Recognition

Abstract

We report a new type of capacitive active pixel sensor based on LTPS TFT backplane technology. It is a pixel design method for image sensors, which combines amplifiers and capacitors to form a pixel unit. Each pixel contains three transistors. This structure includes a capacitor as a sensing element, a reset transistor RST (T3), a row selector RS (T1), and a signal amplifier SF (T2). The advantage is to amplify the signal before reading, which is effective reduce the influence of noise and interference sources, so as to achieve high image quality. Based on the new capacitive active pixel sensor, a capacitive fingerprint sensor array was realized and the fingerprint image was successfully captured.