Method for representing and optimizing a double-progressive spectacle lens

US7021763B2 · kind B2 · utility

Assignee

• RODENSTOCK GMBH · DE

Inventors

• Andrea Welk · Munich, DE
• Peter Baumbach · Hersbruck, DE
• Walter Haimerl · Munich, DE
• Herbert Pfeiffer · Munich, DE
• Gregor Esser · Munich, DE
• Helmut Altheimer · Munich, DE

Key dates

• Filing date: Feb 4, 2002
• Grant date: Apr 4, 2006
• Expiry date: Feb 4, 2022

Classification

• Technology area (CPC G): Physics
• CPC primary: G02C7/061
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A method for representing and optimizing a double-progressive spectacle lens is characterized by the following steps: selecting a suitable coordinate system K2 for the representation of a back surface; selecting a suitable grid G for the representation of a spline of the back surface of a starting lens to be optimized in a coordinate system K2; assigning sagittal height data of the back surface to a spline (back surface spline); defining a position of a center of rotation of an eye; computing principal rays from the center of rotation of the eye through the starting lens at grid points of G; computing a length of a distance between points of penetration of a thus computed principal ray through a front surface and the back surface (oblique thickness); assigning data of the oblique thickness (thickness spline) to a spline; selecting a set of assessment positions at which an optical quality is computed for a target function; suitably selecting particular optical and geometrical stipulations which ideally should be satisfied at the assessment positions; defining the target function as a deviation of the quality of an actual spectacle lens from ideal values; starting the optimization; e…