Compact, simple, 2D raster, image-building fingerprint scanner

摘要

A beam (38) of electromagnetic radiation deflected by a moving mirror plate (56) of a micromachined scanner (54) produces a two dimensional ("2D") raster (132) on a scanned surface (28) of a block (34). The block (34) is transparent to electro-magnetic radiation of pre-established wavelengths. A radiation inlet-face (36) of the block (34) admits the beam (38) that then impinges on the scanned surface (28) to exit the block (34) through a radiation outlet-face (42). After exiting the block (34), the beam (38) impinges upon a radiation detector (142). Total internal reflection ("TIR") of the beam (38) from the scanned surface (28) at fingerprint valleys and frustration of TIR at fingerprint ridges causes the radiation detector (142) to produce a time-varying electrical signal that represents the fingerprint. The scanned surface (28) may be formed by a patch (302) of resilient material, that may be tinted to be transparent only at the pre-established wavelength of the electro-magnetic radiation.