Optical apparatus for fingerprint recognition system
First Claim
1. An optical apparatus for fingerprint recognition system comprising:
- a light source for emitting a spherical beam;
collimating hologram means for producing a plane beam upon receiving the emitted spherical beam from said light source;
diffuser means for scattering the plane beam from said collimating hologram onto a subject fingerprint;
prism means for absorbing the scattered beam encountering ridges in the subject fingerprint ridges and reflecting the scattered beam encountering valleys in the subject fingerprint;
fingerprint image producing hologram means for converting the scattered beam encountering the valleys reflected by said prism into a reflected spherical beam and for condensing the reflected spherical beam representing the subject fingerprint; and
a light sensitive area for converting the condensed reflected spherical beam of the fingerprint image into an electric signal;
said prism means including a cutoff/absorption plate for cutting off and absorbing the scattered beam;
said fingerprint producing hologram means being mounted on a surface of said prism means vertical to a surface receiving the plane beam.
1 Assignment
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Accused Products
Abstract
An optical apparatus for a fingerprint recognition system utilizes a light source for emitting a spherical beam. A collimating hologram produces a plane beam upon receiving the emitted spherical beam from the light source. A diffuser generates a scattered beam by scattering the plane beam. A prism absorbs the light at ridges of a subject fingerprint and reflects the light at valleys of the subject fingerprint. An image producing hologram then processes the reflected spherical beam from the prism corresponding to the valleys and condenses the spherical beam upon an area CCD. The area CCD converts the produced fingerprint image into an electric signal. The fingerprint image producing hologram and a cutoff/absorption plate for cutting off and absorbing the beam are, respectively, mounted on a vertical surface of the prism.
24 Citations
6 Claims
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1. An optical apparatus for fingerprint recognition system comprising:
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a light source for emitting a spherical beam; collimating hologram means for producing a plane beam upon receiving the emitted spherical beam from said light source; diffuser means for scattering the plane beam from said collimating hologram onto a subject fingerprint; prism means for absorbing the scattered beam encountering ridges in the subject fingerprint ridges and reflecting the scattered beam encountering valleys in the subject fingerprint; fingerprint image producing hologram means for converting the scattered beam encountering the valleys reflected by said prism into a reflected spherical beam and for condensing the reflected spherical beam representing the subject fingerprint; and a light sensitive area for converting the condensed reflected spherical beam of the fingerprint image into an electric signal; said prism means including a cutoff/absorption plate for cutting off and absorbing the scattered beam; said fingerprint producing hologram means being mounted on a surface of said prism means vertical to a surface receiving the plane beam. - View Dependent Claims (2, 3, 4, 6)
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5. θ
- =θ
5. θ
2=θ
6, L1=nl1, L2=l2, 25°
<
θ
5, and θ
6<
35°
.
- =θ
Specification