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. 25, 1990
Filed:
Dec. 30, 1988
Shuichi Satoh, Hyogo, JP;
Kazuwo Tsuji, Hyogo, JP;
Sumitomo Electric Industries, Ltd., Osaka, JP;
Abstract
A green diamond has a nitrogen content in its crystals within the range of 5.times.10.sup.16 to 3.times.10.sup.19 atoms/cm.sup.3, an absorption coefficient of H2 centers at a wavelength of 800 nm within the range of 0.3 to 6 cm.sup.-1, an absorption coefficient of the Ib type nitrogen at a wavelength of 500 nm within the range of 0.05 to 1.5 cm.sup.-1, and absorption coefficients of H3 centers, H4 centers, N-V centers and GR1 centers in the visible region of not more than 0.2 cm.sup.-1. Such green diamonds are produced by preparing a clear-yellow Ib type diamond having a nitrogen content in crystals within the range of 5.times.10.sup.16 to 3.times.10.sup.19 atoms/cm.sup.3, irradiating this diamond with an electron beam having not less than 1.times.10.sup.18 electrons/cm.sup.2 at an accelerating voltage of 2 to 4 MeV, and subjecting the diamond to a heat treatment at a temperature of 1500.degree. C.-1800.degree. C. in a vacuum of not more than 10.sup.-3 torr.