Patent ID: 8619362

Claim:
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 f m = r j 2 jm â¢ â¢ Î» to produce close to phase function cycles by 2Ï€ period between a diffractive groove boundary, where â€œÎ»â€ is a design wavelength â€œf m â€ is a focal length â€œjâ€ is a groove order, â€œr j â€ is a radial boundary position of j-order groove, and â€œmâ€ is an m-order diffraction.