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:
Dec. 14, 1976
Filed:
Oct. 28, 1975
Applicant:
Inventors:
David A Krohn, Southbridge, MA (US);
Robert E Graf, Southbridge, MA (US);
Emil W Deeg, Woodstock, CT (US);
Assignee:
American Optical Corporation, Southbridge, MA (US);
Primary Examiner:
Int. Cl.
CPC ...
G02B / ;
U.S. Cl.
CPC ...
351166 ; 65 3 / ; 351168 ; 351171 ; 106 52 ; 106 / ; 428410 ;
Abstract
There is disclosed an ion exchange-strengthened ophthalmic segment glass suitable for the fabrication of fused bifocal and trifocal ophthalmic lenses. More particularly, there is disclosed a lanthanum-silicate based ophthalmic segment glass having indices of refraction of about 1.57 to about 1.65 which is suitable for chemical ion exchange strengthening so as to develop a compressively-stressed ion-exchanged surface layer having a depth of at least 60 micrometers.