A 368 x 184 Optical Under-Display Fingerprint Sensor With Global Shutter and High-Dynamic-Range Operation

Abstract

This study proposes a 368 x 184 optical underdisplay fingerprint sensor designed and prototyped using 0.11-mu m CIS technology. The prototype sensor with global shutter operation and an ADC-embedded in an 8-pixel configuration features low noise, low-power consumption, fast response time, and a smaller signal processing circuit area. Two sets of memory (184 x 92 bytes) are also embedded in the pixel array to save external memory cost. A dynamic range of 126 dB is achieved with 8-segment auto exposure and dark level adjustment with programmable gain control. The prototype fingerprint sensor was successfully embedded in a mobile phone for functional verification, and the power consumption was only 25 mW with a 3.3 V supply voltage. The sensor has a chip size of 9.74 mm x 4.6 mm, a resolution of 1154 dpi, and a sensing area of 73%.