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:
Feb. 28, 1978
Filed:
Mar. 18, 1976
Emil W Deeg, Woodstock, CT (US);
David A Krohn, Southbridge, MA (US);
American Optical Corporation, Southbridge, MA (US);
Abstract
Glass lenses, or lens blanks, containing all the ingredients necessary to produce phototropic, or photochromic behavior, are treated in a conventional production furnace to produce a locally variable heat treatment, wherein at least one portion thereof is raised to a temperature exceeding the glass strain point but not the softening point, and other portions are heated to variable temperatures decreasing from the strain point. The treatment causes development of phototropic, or photochromic, behavior only in those portions of the lenses, or lens blanks, exposed to the temperature above the strain point. The lenses resulting are characterized by trichromatic coefficients, x=0.310 and y=0.321, in the unactivated state and x=0.314 and y=0.319, in an activated state.