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:
Jun. 13, 1989
Filed:
Jun. 23, 1988
Maurice Dufour, Paris, FR;
Abstract
In this lens, the curvature of the main meridian curve of power progression (MP) begins to vary from a point (A3) situated within the intermediate vision zone (VI) at a predetermined distance d1 from the point (A1) on the main meridian curve (MP) situated at the bottom of the far vision zone (VL), and it continues to vary down to a point (A4) situated in the near vision zone (VP) on an extension (MP') of the main meridian curve (MP), and at a predetermined distance d2 from the point (A2) on the main meridian curve (MP) situated at the top of the near vision zone (VP), with the curvature difference between the points (A2 and A4) having a predetermined value .DELTA.C. The values of d1, d2, and .DELTA.C are decreasing functions of the power addition A between the points (A1 and A2).