The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 29, 1981
Filed:
Jan. 21, 1980
Paul M Raccah, Chicago, IL (US);
Scientific Gem Identification, Inc., Los Angeles, CA (US);
Abstract
Method and apparatus for measuring the spectral transmission characteristics of gems, particularly diamonds. Polychromatic light from a light source is transmitted through a diamond to be analyzed, after which the transmitted light beam is separated into a plurality of separate wavelength bands and the intensity of light in the successive bands is measured by a first linear array of photodiodes. Simultaneously, a reference beam of light from the light source is separated into a plurality of corresponding wavelength bands, and the intensity of light in the successive bands are measured by a second linear array of photodiodes. The two measurements produced by each pair of corresponding photodiodes are then compared with each other, to provide a plurality of measurements indicative of the transmission characteristics of the diamond for the plurality of wavelength bands. The transmission measurements for prescribed groupings of wavelength bands are then averaged and compared with each other in a prescribed fashion, to accurately grade the diamond according to conventional grading standards.