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:
Nov. 27, 1984
Filed:
Jun. 30, 1981
Bernard Mignen, St. Maur-des-Fosses, FR;
Essilor International Cie Generale d'Optique, Creteil, FR;
Abstract
Multifocal ophthalmic lenses are disclosed such as a bifocal lens in which the convex front surface includes an upper part for distant vision having a first spherical surface and a lower part for reading having a second spherical surface, the radius of the first spherical surface being greater than the radius of the second spherical surface. A zone of curvature continuity connects the first and second spherical surfaces along at least one meridian, e.g. a central meridian, of the ophthalmic lens, and the second spherical surface extends away from the zone of surface continuity into a surface of revolution which may be spherical or toroidal. Junctions between the surfaces are defined by ledgeless intersections which are lines of curvature discontinuity extending away from the zone of surface continuity. In case of trifocal lenses, a third crescent-shaped spherical surface, having a radius of length intermediate the radii of the first and second spherical surfaces, is interposed between the first and second spherical surfaces.