Multifocal diffractive ophthalmic lenses
AssigneeMinnesota Mining and Manufacturing Company
InventorsJohn A. Futhey, Michael J. Simpson
Life of this patent
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Abstract
A lens according to the invention has diffractive power and two primary foci, where one focus is associated with the first diffractive order and one with the second diffractive order.
Claims12
A multifocal ophthalmic lens having two primary optical powers both resulting from the combined effects of diffraction and refraction, said lens comprising at least one surface having a plurality of diffractive zones including a central zone and a plurality of concentric annular zones each zone separated from an adjacent zone by an optical step having an optical height substantially equal to three-halves of a design wavelength.
A lens having diffractive power and having two primary foci wherein said primary foci correspond to the positive first and second diffractive orders.
Dependencies are inferred from the claim text.