Miniaturized optical fingerprint scanner incorporating an integrated encoding plate

A compact optical fingerprint scanner (FPS) without a lens has been proposed and demonstrated using a plastic encoding plate that integrates an input and output routing mirror in conjunction with a platen. A beam originating from a vertical cavity surface emitting laser is projected toward the platen through the input routing mirror. Considering that the total internal reflection is inhibited at the ridges but takes place at the valleys, the projected beam can be spatially modulated by placing a fingerprint on the platen. The proposed FPS has been designed via ray‐optic simulations and was then constructed by creating an integrated encoding plate. The scanner could manifest the sweat glands of the ridges for an actual fingerprint.