System and method for illuminating a platen in a live scanner and producing high-contrast print images
First Claim
Patent Images
1. A print scanner, comprising:
- a prism having an illumination injection surface, an illumination reflection surface, and a platen surface, said illumination reflection surface of said prism having a reflective coating that diffuses incident rays of light; and
an illumination source, wherein said illumination source injects rays of light into said prism at said illumination injection surface of said prism, the rays of light traveling internally through said prism to hit said illumination reflection surface of said prism where the rays of light are diffused, the rays of light hitting said illumination reflection surface of said prism at an angle less than the critical angle of said illumination reflection surface, the diffused rays of light traveling internally through said prism to illuminate said platen surface of said prism.
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Abstract
Light from an illumination source is injected into a prism of a print scanner through an illumination injection surface that is not directly imaged by an optical system and an image sensor of the print scanner. This light travels across the prism and hits a highly reflective surface of the prism. When this light hits the highly reflective surface, it is scattered and becomes diffused. Some of this diffused light remains in total internal reflection (TIR) within the prism and is reflected off the inside of the platen surface of the prism. The diffused light reflected off the inside of the platen surface is imaged by the optical system and the image sensor.
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Citations
16 Claims
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1. A print scanner, comprising:
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a prism having an illumination injection surface, an illumination reflection surface, and a platen surface, said illumination reflection surface of said prism having a reflective coating that diffuses incident rays of light; and
an illumination source, wherein said illumination source injects rays of light into said prism at said illumination injection surface of said prism, the rays of light traveling internally through said prism to hit said illumination reflection surface of said prism where the rays of light are diffused, the rays of light hitting said illumination reflection surface of said prism at an angle less than the critical angle of said illumination reflection surface, the diffused rays of light traveling internally through said prism to illuminate said platen surface of said prism. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for producing a ridge pattern image with a print scanner, wherein the print scanner includes a prism, an illumination source, an optical system, and an image sensor, the prism having an illumination injection surface, an illumination reflection surface, and a platen surface, the illumination reflection surface having a coating that diffuses incident rays of light, the method comprising:
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(1) injecting rays of light into the prism through the illumination injection surface of the prism such that the injected rays of light travel through the prism to hit the illumination reflection surface, the rays of light hitting the illumination reflection surface at an angle less than the critical angle of the illumination reflection surface;
(2) diffusing the injected rays of light with the illumination reflection surface of the prism; and
(3) illuminating the platen surface with the diffused rays of light reflected off the illumination reflection surface of the prism. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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Specification