Optical fingerprint acquisition apparatus

• US 6,826,000 B2
• Filed: 05/17/2002
• Issued: 11/30/2004
• Est. Priority Date: 09/17/2001
• Status: Expired due to Fees

• Current Assignee: Nitgen & Company Company Limited (Union Community Company Limited)
• Original Assignee: SecuGen Corporation (Pivotec Corp.)
• Inventors: Lee, Dong Won, Shin, Sung Hyu, Lee, Jong Ik
• Primary Examiner(s): Shafer, Ricky D.
• Application Number:
  US10/150,419
• Publication Number:
  US 20030053228A1
• Time in Patent Office: 928 Days
• Field of Search: 359/833, 359/837, 359/857, 359/862, 359/831, 382/127, 356/71
• US Class Current: 359/833
• CPC Class Codes: A61B 5/103 Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes A61B5/08 takes precedence; measuring aids for tailors A41H1/00; measuring instruments specially adapted for dentistry A61C19/04
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: G06V 40/1324 by using geometrical optics, e.g. using prisms G06V40/1312 takes precedence

Abstract

Disclosed is an optical fingerprint acquisition apparatus capable of reducing an image distortion and a size of an optical system by deforming the shape of a prism. The prism according to the invention includes a fingerprint contacting surface to be touched by a fingerprint of a person, a totally reflecting surface facing the fingerprint contacting surface with an angle θ for totally and inwardly reflecting the light scattered from the fingerprint in contact with the fingerprint contacting surface, a primarily projecting/re-incident surface linking the fingerprint contacting surface to the totally reflecting surface with an angle φ for primarily projecting the light totally reflected from the totally reflecting surface so as to be re-incident from outside, and an ultimately projecting surface facing the primarily projecting/re-incident surface for ultimately projecting the light re-incident to the primarily projecting/re-incident surface toward outside.

Claims

1. An optical fingerprint acquisition apparatus for acquiring a fingerprint image by light scattered from a fingerprint, the apparatus comprising:

a prism including a fingerprint contacting surface to be touched by a fingerprint of a person, a totally reflecting surface facing the fingerprint contacting surface with an angle θ

for totally and inwardly reflecting the light scattered from the fingerprint in contact with the fingerprint contacting surface, a primarily projecting/re-incident surface linking the fingerprint contacting surface with an angle φ

to the totally reflecting surface for primarily projecting the light totally reflected from the totally reflecting surface so as to be re-incident from outside the prism, and an ultimately projecting surface facing the primarily projecting/re-incident surface for ultimately projecting the light re-incident to the primarily projecting/re-incident surface toward the outside of the prism; and

a reflecting mirror installed outside the prism, adjacent to the primarily projecting/re-incident surface of the prism and an angle δ

thereto, the reflecting mirror for reflecting the light projected from the primarily projecting/re-incident surface so as to be re-incident to the prism through the primarily projecting/re-incident surface.

2. The optical fingerprint acquisition apparatus of claim 1, wherein the following relation is established among each surface of the prism:

3. The optical fingerprint acquisition apparatus of claim 2, wherein an angle θ

between the fingerprint contacting surface and the totally reflecting surface is defined so as to totally reflect the light scattered at a predetermined angle from an effective fingerprint contacting area of the fingerprint contacting surface toward the primarily projecting/re-incident surface,

the angle δ

is defined so as to reflect all of the light primarily projected from the primarily projecting/re-incident surface toward a central portion of the ultimately projecting surface, and

the angle φ

is defined so as to refract all the light primarily projected from the primarily projecting/re-incident surface and reflecting from the reflecting mirror toward the central portion of the ultimately projecting surface.

4. The optical fingerprint acquisition apparatus of claim 2, wherein a light transmissible material is filled in the space between the primarily projecting/re-incident surface of the prism and the reflecting mirror.

5. The optical fingerprint acquisition apparatus of claim 1 wherein an angle θ

between the fingerprint contacting surface and the totally reflecting surface is defined so as to totally reflect the light scattered at a predetermined angle from an effective fingerprint contacting area of the fingerprint contacting surface toward the primarily projecting/re-incident surface;

the angle δ

is defined so as to reflect all of the light primarily projected form the primarily projecting/re-incident surface toward a central portion of the ultimately projecting surface, and

the angle φ

is defined so as to refract all the light primarily projected from the primarily projecting/re-incident surface and reflected from the reflecting mirror toward the central portion of the ultimately projecting surface.

6. The optical fingerprint acquisition apparatus of claim 1, wherein a light transmissible material is filled in the space between the primarily projecting/re-incident surface of the prism and the reflecting mirror.