| 摘要 |
PROBLEM TO BE SOLVED: To obtain an image with a large contrast difference between fingerprint uneven parts and to reduce the thickness of a fingerprint reader. SOLUTION: A specific surface 1a of a rectangular prism 1 is fingerprint checking surface 2 against which a finger tip Y is pressed. A diffusion plate 3 is arranged nearby and along the opposite surface 1b which faces the fingerprint checking surface 2 among the respective surfaces of the prism 1. The detection light beams from LEDs 4 and 5 while emitted in plane by the diffusion surface 3 are made to enter the prism 1 at a tilt angle of specular reflection by the fingerprint checking surface 2. The reflected light from the fingerprint checking surface 2 after being reflected by the opposite surface 1b of the prism 1 as a 1st reflecting surface is reflected by a side end surface 1d of the prism as a 2nd reflecting surface to exit from a side end surface 1c of the prism 1 finally. In the projection direction of the reflected light from the prism 1, an imaging lens body RZ, a reflecting mirror 9 and an image pickup means 10 are arranged. The thickness of a casing K is reduced almost to the maximum thickness of the prism 1.
|
