US Patent 9223148 Multifocal lens

A multifocal lens has a number n>2 of principal powers, of which at least one principal power is refractive and at least one principal power is diffractive. The multifocal lens includes a first lens portion having at least one first annular zone and at least a second lens portion having at least one second annular zone, wherein the zones each have at least one main sub-zone and at least one phase sub-zone. For forming the n principal powers, a maximum of n−1 lens portions are combined, and an averaged refractive power of a zone of the first lens portion is equal to an averaged refractive power of a zone of the second lens portion.