Phosphor-Converted LED for Iris Acquisition Based on Visible and Near-Infrared Phosphors
Changfu Xu, Yan Yuan, Haiyan Shi, Minchun Lin, Yuan Tang, Zhaoqi Liu, Nian Pan, Xiaohong Zhang, Pengbo Lyu, Lizhong Sun · ACS Applied Electronic Materials · 2024
Capturing both structural and pigmented iris textures is essential for accurate identity authentication and medical testing, particularly for heavily pigmented irises. Traditional near-infrared (NIR) lighting captures only structural details, while multiwavelength LEDs capture both but hinder device miniaturization. We present a solution using a phosphor-converted LED (pc-LED) that emits both visible and NIR light, combining commercial CaAlSiN 3:Eu 2+ and Ca 3 LuAlGe 3 O 12:Cr 3+ phosphors. This compact lighting source improves the emission efficiency and thermal stability through Lu 3+ substitution with Al 3+, allowing for the capture of clear iris images that reveal both structural and pigmented textures. Our results highlight the potential of visible and NIR pc-LEDs to enhance iris biometrics for portable devices and reduce the cost of iris medical testing equipment.