System for print imaging with prism illumination optics
First Claim
Patent Images
1. A platen illumination system comprising:
- a prism comprising a first side, a second side, a third side and a platen side, such that the first side is between the platen side and the third side and the second side is between the platen side and the third side;
a platen surface coupled to the platen side, the platen surface being configured to receive at least a portion of a hand;
an illumination source optically coupled to the first side, the illumination source configured to generate a beam of radiation for illuminating the platen surface; and
a directionally-oriented reflective device optically coupled to the second side, the directionally-oriented reflective device configured to reflect the beam of radiation towards the platen surface, wherein;
the beam of radiation enters the prism through the first side and reflects from the directionally-oriented reflective device towards the platen surface,the platen surface is arranged to receive the beam of radiation at a desired angle of incidence, andthe directionally-oriented reflective device is configured such that at least a portion of the directionally-oriented reflective device reflects the beam of radiation at a selected angle of reflection which is different than an angle of incidence of the beam of radiation on the directionally-oriented reflective device, the selected angle of reflection is such that the beam of radiation is incident upon the platen surface at the desired angle of incidence.
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Abstract
A directionally-oriented reflective device is optically coupled to a prism surface in a skin ridge pattern imaging system to reflect illumination light at relatively small angles, along an optical path to an imaging device, so that minimal light is lost from the optical system. Examples of such directionally-oriented reflective devices include, but are not limited to, echelon reflectors, faceted reflective surfaces, retroreflectors, aluminum paint, nacreous pigment, and slightly rough mirror surfaces.
23 Citations
27 Claims
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1. A platen illumination system comprising:
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a prism comprising a first side, a second side, a third side and a platen side, such that the first side is between the platen side and the third side and the second side is between the platen side and the third side; a platen surface coupled to the platen side, the platen surface being configured to receive at least a portion of a hand; an illumination source optically coupled to the first side, the illumination source configured to generate a beam of radiation for illuminating the platen surface; and a directionally-oriented reflective device optically coupled to the second side, the directionally-oriented reflective device configured to reflect the beam of radiation towards the platen surface, wherein; the beam of radiation enters the prism through the first side and reflects from the directionally-oriented reflective device towards the platen surface, the platen surface is arranged to receive the beam of radiation at a desired angle of incidence, and the directionally-oriented reflective device is configured such that at least a portion of the directionally-oriented reflective device reflects the beam of radiation at a selected angle of reflection which is different than an angle of incidence of the beam of radiation on the directionally-oriented reflective device, the selected angle of reflection is such that the beam of radiation is incident upon the platen surface at the desired angle of incidence. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A system for imaging at least a portion of a hand, comprising:
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a prism comprising a first side, a second side, a third side and a platen side, such that the first side is between the platen side and the third side and the second side is between the platen side and the third side; a platen surface coupled to the platen side, the platen surface being configured to receive at least a portion of a hand; an illumination source optically coupled to the first side, the illumination source configured to generate a beam of radiation for illuminating the platen surface; a directionally-oriented reflective device optically coupled to the second side, the directionally-oriented reflective device configured to reflect the beam of radiation towards the platen surface; an imaging device configured to view the platen surface telecentrically; and an aperture stop between the imaging device and the platen surface, the aperture stop configured to transmit at least a portion of the beam of radiation from the platen surface along a telecentric path before imaging of the at least a portion of the beam of radiation by the imaging device, wherein; the beam of radiation enters the prism through the first side and reflects from the directionally-oriented reflective device towards the platen surface, the platen surface is arranged to receive the beam of radiation at a desired angle of incidence, and the directionally-oriented reflective device is configured such that at least a portion of the directionally-oriented reflective device reflects the beam of radiation at a selected angle of reflection which is different than an angle of incidence of the beam of radiation on the directionally-oriented reflective device, wherein; the selected angle of reflection is such that the beam of radiation is incident upon the platen surface at the desired angle of incidence, and the desired angle of incidence is arranged to result in reflection of the beam of radiation from the platen surface along the telecentric path to the aperture, wherein an intensity of the at least a portion of the beam of radiation transmitted by the aperture and collected by the imaging device is maximized.
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Specification