METHOD FOR REPRESENTING AND OPTIMISING A DOUBLE-PROGRESSIVE SPECTACLE LENS

摘要

The invention relates to a method for representing and optimising a double-progressive spectacle lens. Said method is characterised by the following steps: a suitable co-ordinates system K2 is selected for representing the rear surface; a suitable grid G is selected for representing the spline of the rear surface of a starting lens to be optimised in K2; the sagittal data of the rear surface (rear surface spline) is applied to a spline; the position of the centre of rotation of the eye is defined; the main beams from the centre of rotation of the eye through the starting lens to the grid points of G are examined; the length of the distance between the piercing points of the main beam examined, through the front surfaces and the rear surfaces (diagonal thickness) is calculated; the data of the diagonal thickness is applied to a spline (thickness spline); a set of evaluation points is selected, by which means the optical quality is calculated for the target function; certain optical and geometric standards which ideally correspond to the evaluation points are suitably selected; the target function is defined as a deviation from the quality of current spectacle lenses in terms of said ideal values; the optimisation is initiated; at each optimisation step, the optical properties in the position of use at the evaluation points are evaluated by means of the surface properties to be calculated and current main beam data; the optimisation is completed when the target function is below a certain value, or at the end of a pre-definable maximum number of optimisation steps.