This study details the fabrication of a mutual capacitive-type on-screen fingerprint sensor for full-screen smartphones. The sensor uses an indium tin oxide (ITO) transparent conductor with ~10 Ω/sq. sheet resistance and ~94% transmittance. To minimize Moiré patterns caused by interference with display pixels, numerical calculations were performed to optimize sensor pattern pitch and rotation angle. The resulting pattern, while having small individual sensor pitches, was electrically connected in blocks to ensure sufficient signal sensitivity. A prototype integrated into a commercial smartphone demonstrates successful fingerprint sensing on the display.

Hyun-Joon Kim-Lee, Seog Woo Hong, Dong Kyun Kim, Jinmyoung Kim, Hong Suk Kim, Seok-Whan Chung, Eun-Hyoung Cho, Hae-Sung Kim, Byung-Kyu Lee