Gem identification
AssigneeYeda Research and Development Co. Ltd.
InventorsCharles Bar-Issac, Ephraim Frei, Shmuel Shtrikman
Life of this patent
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Abstract
A device and method for obtaining an identification pattern of polished gemstones. The device comprises, in combination, means for holding the gemstone in a reproducible position, means for creating a collimated parallel light beam, a lens for projecting a pattern obtained by reflecting the collimated parallel light beam from the gemstone onto a plane recording medium facing a plane reference surface of the gemstone. The distinctive pattern may be projected onto the plane recording medium via beam-splitting means. The light used can be white, or monochromatic. Polarized light may be used. Rotation of the pattern about the reference point of the optical axis provides a pattern which may be evaluated automatically.
Claims21
A device for obtaining a reproducible identification pattern of a polished gemstone, comprising, in combination:
- light directing means for creating a parallel light beam and directing the light beam onto the gemstone, said light directing means including light source means for providing a parallel light beam, a first focusing lens in the path of the light beam for focusing the light beam onto a focal point, and a second lens located downstream of said focal point in the path of the light beam at an optical path distance from said focal point equal to the focal length of said second lens;
- holding means disposed downstream of said second lens for holding the gemstone in the path of the light beam with a plane reference surface thereof at a defined reproducible angle to the parallel light beam directed thereon through said second lens;
- and
- a screen optically located on the opposite side of said second lens as the gemstone at an optical path distance from said second lens equal to the focal length thereof, whereby said screen receives reflections from the gemstone passing through said second lens.
A method for recording distinctive patterns for the identification of polished gemstones, comprising:
- directing a beam of light through a lens for creating a parallel beam of light;
- holding the polished gemstone with a plane reference surface thereof at a defined reproducible angle to the parallel light beam coming from the lens;
- and
- recording a pattern of reflections returning through the lens on a plane light sensitive recording medium located at an optical path distance from the lens equal to the focal length thereof.
Dependencies are inferred from the claim text.