Patent ID: 9223121
Filing Date: 2015-12-29
Classification: G02B,G06K

Abstract:
1. An optical structure for fingerprint acquisition, comprising: a prism configured to comprise an input surface to which light is irradiated, a contact surface formed horizontally to be in contact with a finger that reflects the light that has been irradiated to the input surface, and an output surface through which the light that has been irradiated to the input surface and reflected from the finger in contact with the contact surface passes; a lighting unit configured to irradiate a beam of light to the input surface of the prism; a reflector unit configured to reflect a fingerprint image passing through the output surface of the prism; a lens unit configured to comprise two or more lenses, each being configured to receive the fingerprint image reflected from the reflector unit, wherein the lens unit comprises a first lens configured to receive the fingerprint image reflected from the reflector unit and a second lens configured to receive the fingerprint image from the first lens; the first lens and the second lens are aligned to each other in such a manner that the principal axis of the second lens is eccentric with respect to the principal axis of the first lens such that a light ray of the fingerprint image corresponding to a point of the fingerprint image that passes through the center of the first lens is received on a periphery of the second lens outside the center of the second lens and an outer edge of the fingerprint image passing through the first lens is received at the center of a surface of the second lens facing the first lens and passes along the principal axis of the second lens; and an image sensor on which the fingerprint image passing through the second lens is formed, wherein the image sensor is tilted and, the reflector unit is positioned between the prism and the lens unit so as to directly reflect the fingerprint image to the lens unit.