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. 08, 1992
Filed:
Nov. 29, 1990
Lisa A Pettigrew, Tempe, AZ (US);
Donald J Ratkowski, Chandler, AZ (US);
William J Burke, Tempe, AZ (US);
Joseph I Weinschenk, III, Irvine, CA (US);
Pilkington Visioncare, Inc., Menlo Park, CA (US);
Abstract
An oxygen permeable bifocal contact lens with a Dk of at least 10.times.10.sup.-11 in which a distance vision portion having a refractive index of not more than 1.49 is formed as a preform in which there is provided a recess, and a near distance vision portion having a refractive index of at least 1.540 is formed by filling the recess with a monomer mixture and polymerizing. It is preferred that the distance vision portion be formed as an interpenetrating network copolymer by partially polymerizing one monomer mixture to a predetermined relative viscosity and then adding a second monomer mixture and copolymerizing the resulting mixture. The near distance vision portion may also be formed as an interpenetrating network in the same manner.