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. 06, 1977
Filed:
Jan. 27, 1975
Donald R Uhlmann, Newton, MA (US);
Elias Snitzer, Wellesley, MA (US);
Richard J Hovey, Sturbridge, MA (US);
Nori Y Chu, Southbridge, MA (US);
Joseph T Fournier, Jr, Storrs, CT (US);
American Optical Corporation, Southbridge, MA (US);
Abstract
Inorganic photochromic crystalline particles which are particularly useful in ophthalmic quality plastic host materials are formed for instance utilizing a silver halide crystal whose dimensions lie generally in the range between 30 Angstroms and 10,000 Angstroms. The surface of the silver halide crystal is coated with an inorganic material in an effective thickness to render the coating resistant to diffusion from within and to protect the crystal from interaction with host material. The stabilized coated particles can be introduced by known schemes into plastic host materials in order to form photochromic plastic articles useful in the preparation of films, sheets, filters for cameras, wall panels and ophthalmic lenses and other optical devices.