Patent Document ID: 9372342
Application ID: 13597841
Patent Status: 1

Claim One:
1. An optical fingerprint acquisition apparatus comprising: a light refractor having a light incidence surface upon which light from a light source is incident on the light refractor, a fingerprint contact surface including an image area upon which a finger may be placed, and a light emission surface from which light entering the light incidence surface and interacting with a fingerprint of a finger placed on the image area of the fingerprint contact surface is emitted from the light refractor; a plurality of lenses serially arranged along a Z-axis and receiving light emitted from the light emission surface of the light refractor: and an image sensor acquiring from the plurality of lenses an image of a fingerprint of a finger contacting the image area of the fingerprint contact surface of the light refractor, emitted from the light refractor and incident on the plurality of lenses, wherein the plurality of lenses includes a first plano-cylindrical lens having a center and, in cross-section, a cylindrical surface, and a planar surface, wherein light from the light refractor is incident on a light incident surface of the first plano-cylindrical lens, a second plano-cylindrical lens, forming, with the first plano-cylindrical lens, an anamorphic lens system, and having a center and, in cross-section, a cylindrical surface and a planar surface, wherein light from a light emitting surface of the first plano-cylindrical lens is incident on a light incident surface of the second plano-cylindrical lens, and the centers of the first and second plano-cylindrical lenses lie on the Z-axis, and a third lens having an optical axis and projecting light emitted from a light emitting surface of the second plano-cylindrical lens onto the image sensor, a Y-section of the optical fingerprint acquisition apparatus, orthogonal to axes of the cylindrical surfaces of the first and second plano-cylindrical lenses, is orthogonal to an X-section of the optical fingerprint acquisition apparatus, and the Z-axis is orthogonal to the Y-section and the X-section, the image area has a top side and a bottom side in the Y-section and a left side and a right side in the X-section, the light refractor introduces optical distortion into the image of a fingerprint of a finger contacting the image area of the fingerprint contact surface of the light refractor and that is emitted from the light refractor, and the first plano-cylindrical lens and the Z-axis are located relative to the light refractor so that first and second light rays emitted from the light emission surface of the light refractor from the top side and the bottom side of the image area, in the Y-section, are oblique to and asymmetrical with respect to the Z-axis, and one of the first and second light rays is incident proximate the center of the first plano-cylindrical lens in the Y-section, and the other of the first and second light rays is incident on an outer edge of the first plano-cylindrical lens, in the Y-section, whereby the first and second plano-cylindrical lenses correct the optical distortion of the image before the image is incident on the image sensor.