Patent ID: 7315632

Claim:
An apparatus for optically recording the papillary ridges on a finger surface, the apparatus having a transparent body with a support surface for a finger and with a lateral surface, as well as comprising a light source for illuminating the finger surface and an optical system for imaging the papillary ridges that lie on the support surface, and comprising a light detector, wherein the light source emits a light bundle that has a divergent angle that is smaller than the critical angle for total internal reflection at the support surface of the transparent body, and the light bundle leads through the transparent body and falls onto the support surface and irradiates the papillary ridges of the finger there, and the optical system for imaging the papillary ridges is adapted for propagating light bundle that emanates from the support surface and leads through the optical system in order to image the papillary ridges and falls onto a detector surface of the light detector and lies in an angular range that corresponds to the angular range in which light beams that are reflected at the support surface with water, lying thereupon, by total internal reflection, wherein the optical axis of the imaging optical system runs perpendicularly through the lateral surface of the transparent body and wherein the support surface of the transparent body arranged at a first angle to the optical axis of the imaging optical system, and the detector surface of the light detector is arranged at a second angle to the optical axis of the imaging optical system in accordance with the Scheimpflug principle.