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:
Aug. 29, 1989
Filed:
Dec. 10, 1987
John T Winthrop, Wellesley, MA (US);
American Optical Corporation, Southbridge, MA (US);
Abstract
In the embodiments of the bipolar progressive power ophthalmic lens described in the specification, the constant power distance portion and reading portion regions of the progressive power surface are reduced to mathemtical points and the surface astigmatism aberration is reduced to a minimum level by spreading it over a maximally large area of the lens. The points are the poles of a bipolar system of isopower contours and the entire progressive surface is swept out by the curve of intersection formed between a sphere of variable radius and a corresponding circular cylinder of variable diameter with the dimensions of relative positions of intersecting sphere and cylinder chosen so as to produce a gently curving surface to provide a smooth optical effect.