Patent ID: 8619362
Filing Date: 2013-12-31
Classification: A61F,G02C

Abstract:
1. A multifocal diffractive ophthalmic lens comprising: a lens element having an anterior and a posterior surface; a diffractive multifocal zone disposed on one of the anterior and posterior surfaces, said diffractive multifocal zone including structure producing near focus; an opposite refractive zone disposed on another of the anterior and posterior surfaces, incident light passing consecutively through both zones; a multifocal base surface of said diffractive multifocal zone or opposite refractive zone shaped to produce far and intermediate foci by the multifocal diffractive ophthalmic lens, where diffractive groove widths having the multifocal base surface are adjusted from a width defined by a formula to produce close to phase function cycles by 2π period between a diffractive groove boundary, where “λ” is a design wavelength “f m ” is a focal length “j” is a groove order, “r j ” is a radial boundary position of j-order groove, and “m” is an m-order diffraction.